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ZSHCOMPSYS(1)                                                    ZSHCOMPSYS(1)



NAME
       zshcompsys - zsh completion system

DESCRIPTION
       This describes the shell code for the 'new' completion system, referred to as comp-
       sys.  It is written in shell functions based on the features described in  zshcomp-
       wid(1).

       The features are contextual, sensitive to the point at which completion is started.
       Many completions are already provided.  For this reason, a user can perform a great
       many  tasks  without knowing any details beyond how to initialize the system, which
       is described below in INITIALIZATION.

       The context that decides what completion is to be performed may be
       ?      an argument or option position: these describe the position on  the  command
              line  at  which  completion  is  requested.   For example 'first argument to
              rmdir, the word being completed names a directory';


       ?      a special context, denoting an element in the shell's syntax.   For  example
              'a word in command position' or 'an array subscript'.


       A full context specification contains other elements, as we shall describe.

       Besides  commands  names and contexts, the system employs two more concepts, styles
       and tags.  These provide ways for the user to configure the system's behaviour.

       Tags play a dual role.  They serve as a classification system for the matches, typ-
       ically  indicating  a  class  of object that the user may need to distinguish.  For
       example, when completing arguments of the ls command the user  may  prefer  to  try
       files  before  directories,  so  both  of  these are tags.  They also appear as the
       rightmost element in a context specification.

       Styles modify various operations of the completion system, such as  output  format-
       ting, but also what kinds of completers are used (and in what order), or which tags
       are examined.  Styles may accept arguments and are  manipulated  using  the  zstyle
       command described in see zshmodules(1).

       In  summary,  tags describe what the completion objects are, and style how they are
       to be completed.  At various points of execution, the completion system checks what
       styles and/or tags are defined for the current context, and uses that to modify its
       behavior.  The full description of context handling, which determines how tags  and
       other elements of the context influence the behaviour of styles, is described below
       in COMPLETION SYSTEM CONFIGURATION.

       When a completion is requested, a dispatcher function is called; see  the  descrip-
       tion  of  _main_complete  in  the  list of control functions below. This dispatcher
       decides which function should be called to produce the completions, and  calls  it.
       The result is passed to one or more completers, functions that implement individual
       completion strategies: simple completion, error correction, completion  with  error
       correction, menu selection, etc.

       More  generally,  the shell functions contained in the completion system are of two
       types:
       ?      those beginning 'comp' are to be called directly; there are only  a  few  of
              these;


       ?      those  beginning '_' are called by the completion code.  The shell functions
              of this set, which implement  completion  behaviour  and  may  be  bound  to
              keystrokes,  are  referred  to  as  'widgets'.   These  proliferate  as  new
              completions are required.




INITIALIZATION
       If the system was installed completely, it should be enough to call the shell func-
       tion  compinit  from  your initialization file; see the next section.  However, the
       function compinstall can be run by a user to configure various aspects of the  com-
       pletion system.

       Usually, compinstall will insert code into .zshrc, although if that is not writable
       it will save it in another file and tell you that file's location.  Note that it is
       up  to  you  to make sure that the lines added to .zshrc are actually run; you may,
       for example, need to move them to an earlier place in the file  if  .zshrc  usually
       returns  early.  So long as you keep them all together (including the comment lines
       at the start and finish), you can rerun compinstall and it  will  correctly  locate
       and  modify  these  lines.  Note, however, that any code you add to this section by
       hand is likely to be lost if you rerun compinstall, although lines using  the  com-
       mand 'zstyle' should be gracefully handled.

       The new code will take effect next time you start the shell, or run .zshrc by hand;
       there is also an option to make them take effect immediately.  However, if  compin-
       stall  has  removed  definitions,  you  will  need  to restart the shell to see the
       changes.

       To run compinstall you will need to make sure it is in  a  directory  mentioned  in
       your  fpath parameter, which should already be the case if zsh was properly config-
       ured as long as your startup files do not remove the appropriate  directories  from
       fpath.  Then it must be autoloaded ('autoload -U compinstall' is recommended).  You
       can abort the installation any time you are being  prompted  for  information,  and
       your  .zshrc  will not be altered at all; changes only take place right at the end,
       where you are specifically asked for confirmation.


   Use of compinit
       This section describes the use of compinit to initialize completion for the current
       session  when  called directly; if you have run compinstall it will be called auto-
       matically from your .zshrc.

       To initialize the system, the function compinit should be in a directory  mentioned
       in  the fpath parameter, and should be autoloaded ('autoload -U compinit' is recom-
       mended), and then run simply as 'compinit'.  This will define a few  utility  func-
       tions,  arrange  for  all  the necessary shell functions to be autoloaded, and will
       then re-define all widgets that do completion to use the new system.   If  you  use
       the  menu-select  widget, which is part of the zsh/complist module, you should make
       sure that that module is loaded before the call to compinit so that that widget  is
       also  re-defined.  If completion styles (see below) are set up to perform expansion
       as well as completion by default, and the TAB key is bound  to  expand-or-complete,
       compinit will rebind it to complete-word; this is necessary to use the correct form
       of expansion.

       Should you need to use the original completion commands, you can still bind keys to
       the old widgets by putting a '.' in front of the widget name, e.g. '.expand-or-com-
       plete'.

       To speed up the running of compinit, it can be made to produce a dumped  configura-
       tion  that  will  be read in on future invocations; this is the default, but can be
       turned off by calling compinit with the option -D.  The dumped file  is  .zcompdump
       in the same directory as the startup files (i.e. $ZDOTDIR or $HOME); alternatively,
       an explicit file name can be given by 'compinit -d dumpfile'.  The next  invocation
       of  compinit will read the dumped file instead of performing a full initialization.

       If the number of completion files changes, compinit will recognise this and produce
       a  new dump file.  However, if the name of a function or the arguments in the first
       line of a #compdef function (as described below) change, it is  easiest  to  delete
       the  dump  file by hand so that compinit will re-create it the next time it is run.
       The check performed to see if there are new functions can be omitted by giving  the
       option  -C.   In  this  case  the dump file will only be created if there isn't one
       already.

       The dumping is actually done by another function, compdump, but you will only  need
       to  run this yourself if you change the configuration (e.g. using compdef) and then
       want to dump the new one.  The name of the old dumped file will be  remembered  for
       this purpose.

       If  the parameter _compdir is set, compinit uses it as a directory where completion
       functions can be found; this is only necessary if they are not already in the func-
       tion search path.

       For  security reasons compinit also checks if the completion system would use files
       not owned by root or by the current user, or files in directories that  are  world-
       or  group-writable  or  that are not owned by root or by the current user.  If such
       files or directories are found, compinit will ask if the completion  system  should
       really be used.  To avoid these tests and make all files found be used without ask-
       ing, use the option -u, and to make compinit silently ignore all insecure files and
       directories use the option -i.  This security check is skipped entirely when the -C
       option is given.

       The security check can be retried at any time by running  the  function  compaudit.
       This  is  the  same  check  used  by compinit, but when it is executed directly any
       changes to fpath are made local to the function so they do not persist.  The direc-
       tories  to be checked may be passed as arguments; if none are given, compaudit uses
       fpath and _compdir to find completion system directories, adding  missing  ones  to
       fpath as necessary.  To force a check of exactly the directories currently named in
       fpath, set _compdir to an empty string before calling compaudit or compinit.

       The function bashcompinit provides compatibility with bash's  programmable  comple-
       tion  system.   When  run  it will define the functions, compgen and complete which
       correspond to the bash builtins with the same names.  It will then be  possible  to
       use completion specifications and functions written for bash.


   Autoloaded files
       The  convention for autoloaded functions used in completion is that they start with
       an underscore; as already mentioned, the fpath/FPATH  parameter  must  contain  the
       directory  in which they are stored.  If zsh was properly installed on your system,
       then fpath/FPATH automatically contains the required directories for  the  standard
       functions.

       For incomplete installations, if compinit does not find enough files beginning with
       an underscore (fewer than twenty) in the search path, it will try to find  more  by
       adding  the  directory _compdir to the search path.  If that directory has a subdi-
       rectory named Base, all subdirectories will be added to the path.  Furthermore,  if
       the  subdirectory  Base has a subdirectory named Core, compinit will add all subdi-
       rectories of the subdirectories is to the path: this allows the functions to be  in
       the same format as in the zsh source distribution.

       When  compinit  is  run,  it searches all such files accessible via fpath/FPATH and
       reads the first line of each of them.  This line should contain  one  of  the  tags
       described  below.  Files whose first line does not start with one of these tags are
       not considered to be part of the completion system and will  not  be  treated  spe-
       cially.

       The tags are:

       #compdef names... [ -[pP] patterns... [ -N names... ] ]
              The  file  will  be made autoloadable and the function defined in it will be
              called when completing names, each of which is either the name of a  command
              whose  arguments  are to be completed or one of a number of special contexts
              in the form -context- described below.

              Each name may also be of the form 'cmd=service'.  When completing  the  com-
              mand  cmd, the function typically behaves as if the command (or special con-
              text) service was being completed instead.  This provides a way of  altering
              the  behaviour of functions that can perform many different completions.  It
              is implemented by setting the parameter $service when calling the  function;
              the  function  may choose to interpret this how it wishes, and simpler func-
              tions will probably ignore it.

              If the #compdef line contains one of the options -p or -P, the words follow-
              ing  are  taken to be patterns.  The function will be called when completion
              is attempted for a command or context that matches one of the patterns.  The
              options  -p  and -P are used to specify patterns to be tried before or after
              other completions respectively.  Hence -P may be  used  to  specify  default
              actions.

              The  option  -N  is  used after a list following -p or -P; it specifies that
              remaining words no longer define patterns.  It is possible to toggle between
              the three options as many times as necessary.

       #compdef -k style key-sequences...
              This  option  creates  a  widget  behaving like the builtin widget style and
              binds it to the given key-sequences, if any.  The style must be one  of  the
              builtin    widgets    that   perform   completion,   namely   complete-word,
              delete-char-or-list,     expand-or-complete,      expand-or-complete-prefix,
              list-choices,  menu-complete,  menu-expand-or-complete, or reverse-menu-com-
              plete.  If the zsh/complist module is loaded (see zshmodules(1)) the  widget
              menu-select is also available.

              When  one  of  the  key-sequences is typed, the function in the file will be
              invoked to generate the matches.  Note that a key will not be re-bound if it
              already was (that is, was bound to something other than undefined-key).  The
              widget created has the same name as the file and can be bound to  any  other
              keys using bindkey as usual.

       #compdef -K widget-name style key-sequences ...
              This  is  similar  to  -k except that only one key-sequences argument may be
              given for each widget-name style pair.  However, the  entire  set  of  three
              arguments  may  be repeated with a different set of arguments.  Note in par-
              ticular that the widget-name must be distinct in each set.  If it  does  not
              begin  with  '_'  this will be added.  The widget-name should not clash with
              the name of any existing widget: names based on the name of the function are
              most useful.  For example,

                     #compdef -K _foo_complete complete-word "^X^C" \
                       _foo_list list-choices "^X^D"

              (all  on  one  line) defines a widget _foo_complete for completion, bound to
              '^X^C', and a widget _foo_list for listing, bound to '^X^D'.

       #autoload [ options ]
              Functions with the #autoload tag are marked for autoloading but are not oth-
              erwise  treated  specially.  Typically they are to be called from within one
              of the completion functions.  Any options supplied will  be  passed  to  the
              autoload  builtin;  a  typical  use is +X to force the function to be loaded
              immediately.  Note that the -U and -z flags are always added implicitly.

       The # is part of the tag name and no white space is allowed after it.  The #compdef
       tags use the compdef function described below; the main difference is that the name
       of the function is supplied implicitly.

       The special contexts for which completion functions can be defined are:

       -array-value-
              The right hand side of an array-assignment ('foo=(...)')

       -brace-parameter-
              The name of a parameter expansion within braces ('${...}')

       -assign-parameter-
              The name of a parameter in an assignment, i.e. on the left hand side  of  an
              '='

       -command-
              A word in command position

       -condition-
              A word inside a condition ('[[...]]')

       -default-
              Any word for which no other completion is defined

       -equal-
              A word beginning with an equals sign

       -first-
              This is tried before any other completion function.  The function called may
              set the _compskip parameter to one of various values: all: no  further  com-
              pletion is attempted; a string containing the substring patterns: no pattern
              completion functions will be called; a string containing default: the  func-
              tion  for  the '-default-' context will not be called, but functions defined
              for commands will

       -math- Inside mathematical contexts, such as '((...))'

       -parameter-
              The name of a parameter expansion ('$...')

       -redirect-
              The word after a redirection operator.

       -subscript-
              The contents of a parameter subscript.

       -tilde-
              After an initial tilde ('~'), but before the first slash in the word.

       -value-
              On the right hand side of an assignment.

       Default implementations are supplied for each of these contexts.  In most cases the
       context  -context- is implemented by a corresponding function _context, for example
       the context '-tilde-' and the function '_tilde').

       The contexts -redirect-  and  -value-  allow  extra  context-specific  information.
       (Internally, this is handled by the functions for each context calling the function
       _dispatch.)  The extra information is added separated by commas.

       For  the  -redirect-  context,  the  extra  information  is  in  the  form  '-redi-
       rect-,op,command',  where op is the redirection operator and command is the name of
       the command on the line.  If there is no command on the line yet, the command field
       will be empty.

       For the -value- context, the form is '-value-,name,command', where name is the name
       of the parameter.  In the case of elements of an  associative  array,  for  example
       'assoc=(key  <TAB>',  name is expanded to 'name-key'.  In certain special contexts,
       such as completing after 'make CFLAGS=', the command part gives  the  name  of  the
       command, here make; otherwise it is empty.

       It  is not necessary to define fully specific completions as the functions provided
       will try to generate completions  by  progressively  replacing  the  elements  with
       '-default-'.   For  example, when completing after 'foo=<TAB>', _value will try the
       names  '-value-,foo,'  (note  the  empty  command  part),   '-value-,foo,-default-'
       and'-value-,-default-,-default-',  in that order, until it finds a function to han-
       dle the context.

       As an example:

              compdef '_files -g "*.log"' '-redirect-,2>,-default-'

       completes files matching '*.log' after '2> <TAB>' for any command with no more spe-
       cific handler defined.

       Also:

              compdef _foo -value-,-default-,-default-

       specifies  that _foo provides completions for the values of parameters for which no
       special function has been defined.  This is usually handled by the function  _value
       itself.

       The  same  lookup  rules  are used when looking up styles (as described below); for
       example

              zstyle ':completion:*:*:-redirect-,2>,*:*' file-patterns '*.log'

       is another way to make completion after '2> <TAB>' complete files matching '*.log'.


   Functions
       The following function is defined by compinit and may be called directly.

       compdef [ -ane ] function names... [ -[pP] patterns... [ -N names... ] ]
       compdef -d names...
       compdef -k [ -an ] function style key-sequences...
       compdef -K [ -an ] function name style key-sequences ...
              The first form defines the function to call for completion in the given con-
              texts as described for the #compdef tag above.

              Alternatively, all the arguments may have the form 'cmd=service'.  Here ser-
              vice  should  already  have been defined by 'cmd1=service' lines in #compdef
              files, as described above.  The argument for cmd will be  completed  in  the
              same way as service.

              The  function  argument  may alternatively be a string containing almost any
              shell code.  If the string contains an  equal  sign,  the  above  will  take
              precedence.   The  option -e may be used to specify the first argument is to
              be evaluated as shell code even if it contains an equal  sign.   The  string
              will  be  executed  using  the eval builtin command to generate completions.
              This provides a way of avoiding having to define a new completion  function.
              For  example,  to  complete files ending in '.h' as arguments to the command
              foo:

                     compdef '_files -g "*.h"' foo

              The option -n prevents any completions already defined for  the  command  or
              context from being overwritten.

              The  option  -d  deletes  any completion defined for the command or contexts
              listed.

              The names may also contain -p, -P and -N options as described for the  #com-
              pdef  tag.   The effect on the argument list is identical, switching between
              definitions of patterns tried initially, patterns tried finally, and  normal
              commands and contexts.

              The  parameter  $_compskip  may be set by any function defined for a pattern
              context.  If it is set to a value containing the substring  'patterns'  none
              of  the pattern-functions will be called; if it is set to a value containing
              the substring 'all', no other function will be called.

              The form with -k defines a widget with the same name as  the  function  that
              will  be  called for each of the key-sequences; this is like the #compdef -k
              tag.  The function should generate the completions needed and will otherwise
              behave  like  the  builtin widget whose name is given as the style argument.
              The  widgets  usable  for  this  are:  complete-word,   delete-char-or-list,
              expand-or-complete,  expand-or-complete-prefix, list-choices, menu-complete,
              menu-expand-or-complete, and reverse-menu-complete, as well  as  menu-select
              if  the zsh/complist module is loaded.  The option -n prevents the key being
              bound if it is already to bound to something other than undefined-key.

              The form with -K is similar and defines multiple widgets based on  the  same
              function,  each of which requires the set of three arguments name, style and
              key-sequences, where the latter two are as for -k and the first  must  be  a
              unique widget name beginning with an underscore.

              Wherever  applicable, the -a option makes the function autoloadable, equiva-
              lent to autoload -U function.

       The function compdef can be used to associate existing  completion  functions  with
       new commands.  For example,

              compdef _pids foo

       uses the function _pids to complete process IDs for the command foo.

       Note  also the _gnu_generic function described below, which can be used to complete
       options for commands that understand the '--help' option.


COMPLETION SYSTEM CONFIGURATION
       This section gives a short overview of how the completion system  works,  and  then
       more detail on how users can configure how and when matches are generated.


   Overview
       When  completion  is  attempted somewhere on the command line the completion system
       first works out the context.  This takes account of a number  of  things  including
       the  command  word  (such as 'grep' or 'zsh') and options to which the current word
       may be an argument (such as the '-o' option to zsh which takes a shell option as an
       argument).

       This  context  information is condensed into a string consisting of multiple fields
       separated by colons, referred to simply as 'the context' in the  remainder  of  the
       documentation.   This is used to look up styles, context-sensitive options that can
       be used to configure the completion system.  The context used for lookup  may  vary
       during the same call to the completion system.

       The  context  string  always consists of a fixed set of fields, separated by colons
       and with a leading colon before the first, in  the  form  :completion:function:com-
       pleter:command:argument:tag.  These have the following meaning:

       ?      The literal string completion, saying that this style is used by the comple-
              tion system.  This distinguishes the context from those used by,  for  exam-
              ple, zle widgets and ZFTP functions.


       ?      The  function,  if  completion  is  called  from  a named widget rather than
              through the normal completion system.  Typically this is blank,  but  it  is
              set  by  special widgets such as predict-on and the various functions in the
              Widget directory of the distribution to the name of that function, often  in
              an abbreviated form.


       ?      The completer currently active, the name of the function without the leading
              underscore and with other underscores converted to hyphens.   A  'completer'
              is  in  overall  control of how completion is to be performed; 'complete' is
              the simplest, but other completers exist to perform related  tasks  such  as
              correction,  or  to modify the behaviour of a later completer.  See the sec-
              tion 'Control Functions' below for more information.


       ?      The command or a special -context-, just at it appears following  the  #com-
              pdef  tag  or  the compdef function.  Completion functions for commands that
              have sub-commands usually modify this field to contain the name of the  com-
              mand followed by a minus sign and the sub-command.  For example, the comple-
              tion function for the cvs command sets this field to cvs-add when completing
              arguments to the add subcommand.


       ?      The  argument;  this  indicates which command line or option argument we are
              completing.  For command arguments this generally takes the form argument-n,
              where n is the number of the argument, and for arguments to options the form
              option-opt-n where n is the number of the argument to option opt.   However,
              this is only the case if the command line is parsed with standard UNIX-style
              options and arguments, so many completions do not set this.


       ?      The tag.  As described previously, tags are used to discriminate between the
              types  of  matches  a completion function can generate in a certain context.
              Any completion function may use any tag name it likes, but  a  list  of  the
              more common ones is given below.


       The  context is gradually put together as the functions are executed, starting with
       the main entry point, which adds :completion: and the function  element  if  neces-
       sary.   The  completer  then adds the completer element.  The contextual completion
       adds the command and argument options.  Finally, the tag is added when the types of
       completion are known.  For example, the context name

              :completion::complete:dvips:option-o-1:files

       says that normal completion was attempted as the first argument to the option -o of
       the command dvips:

              dvips -o ...

       and the completion function will generate filenames.

       Usually completion will be tried for all possible tags in an  order  given  by  the
       completion  function.   However,  this can be altered by using the tag-order style.
       Completion is then restricted to the list of given tags in the given order.

       The _complete_help bindable command shows all the contexts and tags  available  for
       completion at a particular point.  This provides an easy way of finding information
       for tag-order and other styles.  It is described in the section 'Bindable Commands'
       below.

       Styles  determine  such things as how the matches are generated, similarly to shell
       options but with much more control.  They can have any number of strings  as  their
       value.  They are defined with the zstyle builtin command (see zshmodules(1)).

       When looking up styles the completion system uses full context names, including the
       tag.  Looking up the value of a style therefore consists of two things:   the  con-
       text,  which  may  be matched as a pattern, and the name of the style itself, which
       must be given exactly.

       For example, many completion functions can generate matches in a simple and a  ver-
       bose  form  and use the verbose style to decide which form should be used.  To make
       all such functions use the verbose form, put

              zstyle ':completion:*' verbose yes

       in a startup file (probably .zshrc).  This gives the verbose style the value yes in
       every context inside the completion system, unless that context has a more specific
       definition.  It is best to avoid giving the context as '*' in case  the  style  has
       some meaning outside the completion system.

       Many  such general purpose styles can be configured simply by using the compinstall
       function.

       A more specific example of the use of the verbose style is by  the  completion  for
       the  kill  builtin.   If  the  style  is  set, the builtin lists full job texts and
       process command lines; otherwise it shows the bare job numbers and PIDs.   To  turn
       the style off for this use only:

              zstyle ':completion:*:*:kill:*' verbose no

       For even more control, the style can use one of the tags 'jobs' or 'processes'.  To
       turn off verbose display only for jobs:

              zstyle ':completion:*:*:kill:*:jobs' verbose no

       The -e option to zstyle even allows completion function code to appear as the argu-
       ment  to  a  style; this requires some understanding of the internals of completion
       functions (see see zshcompwid(1))).  For example,

              zstyle -e ':completion:*' hosts 'reply=($myhosts)'

       This forces the value of the hosts style to be read from the variable myhosts  each
       time  a  host  name  is  needed;  this is useful if the value of myhosts can change
       dynamically.  For another useful example, see the example in the description of the
       file-list  style  below.   This form can be slow and should be avoided for commonly
       examined styles such as menu and list-rows-first.

       Note that the order in which styles are defined does not matter; the  style  mecha-
       nism  uses the most specific possible match for a particular style to determine the
       set of values.  More precisely, strings are preferred over patterns  (for  example,
       ':completion::complete:foo'  is  more specific than ':completion::complete:*'), and
       longer patterns are preferred over shorter patterns.

       Style names like those of tags are arbitrary and depend on the completion function.
       However, the following two sections list some of the most common tags and styles.


   Standard Tags
       Some  of  the  following are only used when looking up particular styles and do not
       refer to a type of match.

       accounts
              used to look up the users-hosts style

       all-expansions
              used by the _expand completer when adding the single string  containing  all
              possible expansions

       all-files
              for  the  names  of all files (as distinct from a particular subset, see the
              globbed-files tag).

       arguments
              for arguments to a command

       arrays for names of array parameters

       association-keys
              for keys of associative arrays; used when completing inside a subscript to a
              parameter of this type

       bookmarks
              when completing bookmarks (e.g. for URLs and the zftp function suite)

       builtins
              for names of builtin commands

       characters
              for  single  characters  in  arguments of commands such as stty.   Also used
              when completing character classes after an opening bracket

       colormapids
              for X colormap ids

       colors for color names

       commands
              for names of external commands.  Also used by complex commands such  as  cvs
              when completing names subcommands.

       contexts
              for contexts in arguments to the zstyle builtin command

       corrections
              used by the _approximate and _correct completers for possible corrections

       cursors
              for cursor names used by X programs

       default
              used in some contexts to provide a way of supplying a default when more spe-
              cific tags are also valid.  Note that this tag is used when only  the  func-
              tion field of the context name is set

       descriptions
              used  when looking up the value of the format style to generate descriptions
              for types of matches

       devices
              for names of device special files

       directories
              for names of directories -- local-directories is used instead when  complet-
              ing  arguments  of  cd and related builtin commands when the cdpath array is
              set

       directory-stack
              for entries in the directory stack

       displays
              for X display names

       domains
              for network domains

       expansions
              used by the _expand completer for individual words (as opposed to  the  com-
              plete  set of expansions) resulting from the expansion of a word on the com-
              mand line

       extensions
              for X server extensions

       file-descriptors
              for numbers of open file descriptors

       files  the generic file-matching tag used by functions completing filenames

       fonts  for X font names

       fstypes
              for file system types (e.g. for the mount command)

       functions
              names of functions -- normally shell functions,  although  certain  commands
              may understand other kinds of function

       globbed-files
              for filenames when the name has been generated by pattern matching

       groups for names of user groups

       history-words
              for words from the history

       hosts  for hostnames

       indexes
              for array indexes

       jobs   for jobs (as listed by the 'jobs' builtin)

       interfaces
              for network interfaces

       keymaps
              for names of zsh keymaps

       keysyms
              for names of X keysyms

       libraries
              for names of system libraries

       limits for system limits

       local-directories
              for  names  of  directories  that  are subdirectories of the current working
              directory when completing arguments of cd and related builtin commands (com-
              pare  path-directories)  --  when  the cdpath array is unset, directories is
              used instead

       manuals
              for names of manual pages

       mailboxes
              for e-mail folders

       maps   for map names (e.g. NIS maps)

       messages
              used to look up the format style for messages

       modifiers
              for names of X modifiers

       modules
              for modules (e.g. zsh modules)

       my-accounts
              used to look up the users-hosts style

       named-directories
              for named directories (you wouldn't have guessed that, would you?)

       names  for all kinds of names

       newsgroups
              for USENET groups

       nicknames
              for nicknames of NIS maps

       options
              for command options

       original
              used by the _approximate, _correct and _expand completers when offering  the
              original string as a match

       other-accounts
              used to look up the users-hosts style

       other-files
              for the names of any non-directory files.  This is used instead of all-files
              when the list-dirs-first style is in effect.

       packages
              for packages (e.g. rpm or installed Debian packages)

       parameters
              for names of parameters

       path-directories
              for names of directories found by searching the cdpath array when completing
              arguments of cd and related builtin commands (compare local-directories)

       paths  used to look up the values of the expand, ambiguous and special-dirs styles

       pods   for perl pods (documentation files)

       ports  for communication ports

       prefixes
              for prefixes (like those of a URL)

       printers
              for print queue names

       processes
              for process identifiers

       processes-names
              used to look up the command style when generating the names of processes for
              killall

       sequences
              for sequences (e.g. mh sequences)

       sessions
              for sessions in the zftp function suite

       signals
              for signal names

       strings
              for strings (e.g. the replacement strings for the cd builtin command)

       styles for styles used by the zstyle builtin command

       suffixes
              for filename extensions

       tags   for tags (e.g. rpm tags)

       targets
              for makefile targets

       time-zones
              for time zones (e.g. when setting the TZ parameter)

       types  for types of whatever (e.g. address types for the xhost command)

       urls   used to look up the urls and local styles when completing URLs

       users  for usernames

       values for one of a set of values in certain lists

       variant
              used by _pick_variant to look up the command to run  when  determining  what
              program is installed for a particular command name.

       visuals
              for X visuals

       warnings
              used to look up the format style for warnings

       widgets
              for zsh widget names

       windows
              for IDs of X windows

       zsh-options
              for shell options


   Standard Styles
       Note  that  the values of several of these styles represent boolean values.  Any of
       the strings 'true', 'on', 'yes', and '1' can be used for the value 'true'  and  any
       of  the  strings 'false', 'off', 'no', and '0' for the value 'false'.  The behavior
       for any other value is undefined except where explicitly  mentioned.   The  default
       value may be either true or false if the style is not set.

       Some  of  these  styles  are tested first for every possible tag corresponding to a
       type of match, and if no style was found, for the default tag.   The  most  notable
       styles of this type are menu, list-colors and styles controlling completion listing
       such as list-packed and last-prompt.  When tested for the  default  tag,  only  the
       function  field  of  the  context will be set so that a style using the default tag
       will normally be defined along the lines of:

              zstyle ':completion:*:default' menu ...

       accept-exact
              This is tested for the default tag in addition to the  tags  valid  for  the
              current context.  If it is set to 'true' and any of the trial matches is the
              same as the string on the command  line,  this  match  will  immediately  be
              accepted (even if it would otherwise be considered ambiguous).

              When completing pathnames (where the tag used is 'paths') this style accepts
              any number of patterns as the value  in  addition  to  the  boolean  values.
              Pathnames  matching  one of these patterns will be accepted immediately even
              if the command line contains some more partially typed  pathname  components
              and these match no file under the directory accepted.

              This  style  is also used by the _expand completer to decide if words begin-
              ning with a tilde or parameter expansion should be expanded.   For  example,
              if  there  are  parameters  foo  and  foobar, the string '$foo' will only be
              expanded if accept-exact is set to 'true'; otherwise the  completion  system
              will  be  allowed  to complete $foo to $foobar. If the style is set to 'con-
              tinue', _expand will add the expansion as a match and the completion  system
              will also be allowed to continue.

       accept-exact-dirs
              This  is  used by filename completion.  Unlike accept-exact it is a boolean.
              By default, filename completion examines all components of a path to see  if
              there  are  completions  of that component, even if the component matches an
              existing directory.  For example, when completion after /usr/bin/, the func-
              tion examines possible completions to /usr.

              When  this  style  is  true,  any  prefix of a path that matches an existing
              directory is accepted without any attempt to complete it further.  Hence, in
              the given example, the path /usr/bin/ is accepted immediately and completion
              tried in that directory.

              If you wish to inhibit this  behaviour  entirely,  set  the  path-completion
              style (see below) to false.

       add-space
              This style is used by the _expand completer.  If it is true (the default), a
              space will be inserted after all words resulting from the  expansion,  or  a
              slash in the case of directory names.  If the value is 'file', the completer
              will only add a space to names of existing files.  Either a boolean true  or
              the  value  'file' may be combined with 'subst', in which case the completer
              will not add a space to words generated from the expansion of a substitution
              of the form '$(...)' or '${...}'.

              The _prefix completer uses this style as a simple boolean value to decide if
              a space should be inserted before the suffix.

       ambiguous
              This applies when completing non-final  components  of  filename  paths,  in
              other  words  those with a trailing slash.  If it is set, the cursor is left
              after the first ambiguous component, even if menu completion is in use.  The
              style is always tested with the paths tag.

       assign-list
              When completing after an equals sign that is being treated as an assignment,
              the completion system normally completes only one filename.  In  some  cases
              the  value  may be a list of filenames separated by colons, as with PATH and
              similar parameters.  This style can be set to a list  of  patterns  matching
              the names of such parameters.

              The  default is to complete lists when the word on the line already contains
              a colon.

       auto-description
              If set, this style's value will be used as the description for options  that
              are  not  described  by  the completion functions, but that have exactly one
              argument.  The sequence '%d' in the value will be replaced by  the  descrip-
              tion for this argument.  Depending on personal preferences, it may be useful
              to set this style to something like 'specify: %d'.  Note that this  may  not
              work for some commands.

       avoid-completer
              This  is used by the _all_matches completer to decide if the string consist-
              ing of all matches should be added to the list  currently  being  generated.
              Its  value is a list of names of completers.  If any of these is the name of
              the completer that generated the matches in this completion, the string will
              not be added.

              The  default  value  for this style is '_expand _old_list _correct _approxi-
              mate', i.e. it contains the completers for which a string with  all  matches
              will almost never be wanted.

       cache-path
              This  style defines the path where any cache files containing dumped comple-
              tion  data  are  stored.   It   defaults   to   '$ZDOTDIR/.zcompcache',   or
              '$HOME/.zcompcache'  if  $ZDOTDIR is not defined.  The completion cache will
              not be used unless the use-cache style is set.

       cache-policy
              This style defines the function that will be used  to  determine  whether  a
              cache  needs  rebuilding.   See  the  section on the _cache_invalid function
              below.

       call-command
              This style is used in the function for commands such as make and  ant  where
              calling  the  command  directly to generate matches suffers problems such as
              being slow or, as in the case of make can potentially cause actions  in  the
              makefile  to  be  executed.  If it is set to 'true' the command is called to
              generate matches. The default value of this style is 'false'.

       command
              In many places, completion functions need to call external commands to  gen-
              erate  the list of completions.  This style can be used to override the com-
              mand that is called in some such cases.   The  elements  of  the  value  are
              joined  with  spaces  to form a command line to execute.  The value can also
              start with a hyphen, in which case the usual command will be  added  to  the
              end; this is most useful for putting 'builtin' or 'command' in front to make
              sure the appropriate version of a command is called, for  example  to  avoid
              calling a shell function with the same name as an external command.

              As  an example, the completion function for process IDs uses this style with
              the processes tag to generate the IDs to complete and the list of  processes
              to  display (if the verbose style is 'true').  The list produced by the com-
              mand should look like the output of the ps command.  The first line  is  not
              displayed, but is searched for the string 'PID' (or 'pid') to find the posi-
              tion of the process IDs in the following lines.  If the line does  not  con-
              tain  'PID',  the  first numbers in each of the other lines are taken as the
              process IDs to complete.

              Note that the completion  function  generally  has  to  call  the  specified
              command for each attempt to generate the completion list.  Hence care should
              be taken to specify only commands that take a short time to run, and in par-
              ticular to avoid any that may never terminate.

       command-path
              This  is  a  list  of  directories  to search for commands to complete.  The
              default for this style is the value of the special parameter path.

       commands
              This is used by the function completing sub-commands for the system initial-
              isation  scripts (residing in /etc/init.d or somewhere not too far away from
              that).  Its values give the default commands to complete for those  commands
              for which the completion function isn't able to find them out automatically.
              The default for this style are the two strings 'start' and 'stop'.

       complete
              This is used by the _expand_alias function when invoked as a  bindable  com-
              mand.   If set to 'true' and the word on the command line is not the name of
              an alias, matching alias names will be completed.

       complete-options
              This is used by the completer for cd, chdir and pushd.  For these commands a
              -  is  used  to introduce a directory stack entry and completion of these is
              far more common than completing options.  Hence unless  the  value  of  this
              style is true options will not be completed, even after an initial -.  If it
              is true, options will be completed after an initial - unless there is a pre-
              ceding -- on the command line.

       completer
              The  strings  given as the value of this style provide the names of the com-
              pleter functions to use. The available completer functions are described  in
              the section 'Control Functions' below.

              Each  string  may  be either the name of a completer function or a string of
              the form 'function:name'.  In the first case the completer field of the con-
              text  will  contain the name of the completer without the leading underscore
              and with all other underscores replaced by hyphens.  In the second case  the
              function  is the name of the completer to call, but the context will contain
              the user-defined name in the completer field of the context.   If  the  name
              starts with a hyphen, the string for the context will be build from the name
              of the completer function as in the first case with the name appended to it.
              For example:

                     zstyle ':completion:*' completer _complete _complete:-foo

              Here,  completion  will call the _complete completer twice, once using 'com-
              plete' and once using 'complete-foo' in the completer field of the  context.
              Normally, using the same completer more than once only makes sense when used
              with the 'functions:name' form, because otherwise the context name  will  be
              the same in all calls to the completer; possible exceptions to this rule are
              the _ignored and _prefix completers.

              The default value for this style is '_complete  _ignored':  only  completion
              will  be done, first using the ignored-patterns style and the $fignore array
              and then without ignoring matches.

       condition
              This style is used by the _list completer function to decide if insertion of
              matches should be delayed unconditionally. The default is 'true'.

       delimiters
              This style is used when adding a delimiter for use with history modifiers or
              glob qualifiers that have delimited arguments.  It is an array of  preferred
              delimiters  to  add.  Non-special characters are preferred as the completion
              system may otherwise become confused.  The default list is :, +,  /,  -,  %.
              The list may be empty to force a delimiter to be typed.

       disabled
              If  this  is set to 'true', the _expand_alias completer and bindable command
              will try to expand disabled aliases, too.  The default is 'false'.

       domains
              A list of names of network domains for completion.   If  this  is  not  set,
              domain names will be taken from the file /etc/resolv.conf.

       environ
              The environ style is used when completing for 'sudo'.  It is set to an array
              of 'VAR=value' assignments to be exported into the local environment  before
              the completion for the target command is invoked.
              zstyle :complete:sudo: environ \
                PATH="/sbin:/usr/sbin:$PATH" HOME="/root"

       expand This  style  is  used  when completing strings consisting of multiple parts,
              such as path names.

              If one of its values is the string 'prefix', the partially typed  word  from
              the  line  will be expanded as far as possible even if trailing parts cannot
              be completed.

              If one of its values is the string 'suffix', matching names  for  components
              after  the  first  ambiguous  one  will  also be added.  This means that the
              resulting string is the longest unambiguous string possible.  However,  menu
              completion can be used to cycle through all matches.

       fake   This  style  may be set for any completion context.  It specifies additional
              strings that will always be completed in that context.   The  form  of  each
              string is 'value:description'; the colon and description may be omitted, but
              any literal colons in value must be quoted with a backslash.   Any  descrip-
              tion provided is shown alongside the value in completion listings.

              It  is  important  to use a sufficiently restrictive context when specifying
              fake strings.  Note that the styles fake-files and  fake-parameters  provide
              additional features when completing files or parameters.

       fake-always
              This  works  identically  to the fake style except that the ignored-patterns
              style is not applied to it.  This makes it possible to  override  a  set  of
              matches completely by setting the ignored patterns to '*'.

              The  following shows a way of supplementing any tag with arbitrary data, but
              having it behave for display purposes like a separate tag.  In this  example
              we  use  the features of the tag-order style to divide the named-directories
              tag into two when performing completion with the standard completer complete
              for  arguments  of  cd.  The tag named-directories-normal behaves as normal,
              but the tag named-directories-mine contains  a  fixed  set  of  directories.
              This  has  the effect of adding the match group 'extra directories' with the
              given completions.

                     zstyle ':completion::complete:cd:*' tag-order \
                       'named-directories:-mine:extra\ directories
                       named-directories:-normal:named\ directories *'
                     zstyle ':completion::complete:cd:*:named-directories-mine' \
                       fake-always mydir1 mydir2
                     zstyle ':completion::complete:cd:*:named-directories-mine' \
                       ignored-patterns '*'

       fake-files
              This style is used when completing files and looked up without a  tag.   Its
              values  are  of  the  form 'dir:names...'.  This will add the names (strings
              separated by spaces) as possible matches when completing  in  the  directory
              dir,  even if no such files really exist.  The dir may be a pattern; pattern
              characters or colons in dir should be quoted with a backslash to be  treated
              literally.

              This  can  be  useful  on  systems  that  support special file systems whose
              top-level pathnames can not be listed or generated with glob  patterns.   It
              can  also  be  used for directories for which one does not have read permis-
              sion.

              The pattern form can be used to add a certain 'magic' entry to all  directo-
              ries on a particular file system.

       fake-parameters
              This is used by the completion function for parameter names.  Its values are
              names of parameters that might not  yet  be  set  but  should  be  completed
              nonetheless.   Each name may also be followed by a colon and a string speci-
              fying the type of the parameter (like 'scalar', 'array' or  'integer').   If
              the  type  is  given,  the name will only be completed if parameters of that
              type are required in the particular context.  Names for  which  no  type  is
              specified will always be completed.

       file-list
              This style controls whether files completed using the standard builtin mech-
              anism are to be listed with a long list similar to ls -l.   Note  that  this
              feature  uses the shell module zsh/stat for file information; this loads the
              builtin stat which will replace any external stat executable.  To avoid this
              the following code can be included in an initialization file:

                     zmodload -i zsh/stat
                     disable stat

              The style may either be set to a true value (or 'all'), or one of the values
              'insert' or 'list', indicating that files are to be listed in long format in
              all circumstances, or when attempting to insert a file name, or when listing
              file names without attempting to insert one.

              More generally, the value may be an  array  of  any  of  the  above  values,
              optionally  followed by =num.  If num is present it gives the maximum number
              of matches for which long listing style will be used.  For example,

                     zstyle ':completion:*' file-list list=20 insert=10

              specifies that long format will be used when  listing  up  to  20  files  or
              inserting a file with up to 10 matches (assuming a listing is to be shown at
              all, for example on an ambiguous completion),  else  short  format  will  be
              used.

                     zstyle -e ':completion:*' file-list '(( ${+NUMERIC} )) && reply=(true)'

              specifies  that long format will be used any time a numeric argument is sup-
              plied, else short format.

       file-patterns
              This is used by the standard function for completing filenames, _files.   If
              the  style  is unset up to three tags are offered, 'globbed-files','directo-
              ries' and 'all-files', depending on the types  of  files   expected  by  the
              caller  of  _files.   The  first two ('globbed-files' and 'directories') are
              normally offered together to make it easier to complete files in  sub-direc-
              tories.

              The file-patterns style provides alternatives to the default tags, which are
              not used.  Its value consists of elements of the  form  'pattern:tag';  each
              string may contain any number of such specifications separated by spaces.

              The  pattern  is  a  pattern  that is to be used to generate filenames.  Any
              occurrence of the sequence '%p' is replaced by any pattern(s) passed by  the
              function  calling _files.  Colons in the pattern must be preceded by a back-
              slash to make them distinguishable from the colon before the tag.   If  more
              than  one  pattern is needed, the patterns can be given inside braces, sepa-
              rated by commas.

              The tags of all strings in the value will be offered by _files and used when
              looking  up  other styles.  Any tags in the same word will be offered at the
              same time and before later words.  If no ':tag' is  given  the  'files'  tag
              will be used.

              The  tag may also be followed by an optional second colon and a description,
              which will be used for the '%d' in the value of the format style (if that is
              set) instead of the default description supplied by the completion function.
              If the description given here contains itself a '%d', that is replaced  with
              the description supplied by the completion function.

              For  example,  to  make  the  rm command first complete only names of object
              files and then the names of all files if there is no matching object file:

                     zstyle ':completion:*:*:rm:*' file-patterns \
                         '*.o:object-files' '%p:all-files'

              To alter the default behaviour of file completion -- offer files matching  a
              pattern  and  directories  on  the first attempt, then all files -- to offer
              only matching files on the first attempt, then directories, and finally  all
              files:

                     zstyle ':completion:*' file-patterns \
                         '%p:globbed-files' '*(-/):directories' '*:all-files'

              This  works even where there is no special pattern: _files matches all files
              using the pattern '*' at the first step and stops when it sees this pattern.
              Note also it will never try a pattern more than once for a single completion
              attempt.

              During the execution of completion functions, the EXTENDED_GLOB option is in
              effect, so the characters '#', '~' and '^' have special meanings in the pat-
              terns.

       file-sort
              The standard filename completion function uses this style without a  tag  to
              determine  in  which  order the names should be listed; menu completion will
              cycle through them in the same order.  The possible values  are:  'size'  to
              sort  by the size of the file; 'links' to sort by the number of links to the
              file; 'modification' (or 'time' or 'date') to sort by the last  modification
              time; 'access' to sort by the last access time; and 'inode' (or 'change') to
              sort by the last inode change time.  If the style is set to any other value,
              or is unset, files will be sorted alphabetically by name.  If the value con-
              tains the string 'reverse', sorting is done in the opposite order.   If  the
              value  contains the string 'follow', timestamps are associated with the tar-
              gets of symbolic links; the default is to use the timestamps  of  the  links
              themselves.

       filter This is used by the LDAP plugin for e-mail address completion to specify the
              attributes to match against when filtering entries.  So for example, if  the
              style is set to 'sn', matching is done against surnames.  Standard LDAP fil-
              tering is used so normal completion matching is bypassed.  If this style  is
              not  set,  the LDAP plugin is skipped.  You may also need to set the command
              style to specify how to connect to your LDAP server.

       force-list
              This forces a list of completions to be shown at any point where listing  is
              done,  even  in cases where the list would usually be suppressed.  For exam-
              ple, normally the list is only shown if there are  at  least  two  different
              matches.   By setting this style to 'always', the list will always be shown,
              even if there is only a single match that will immediately be accepted.  The
              style  may  also be set to a number.  In this case the list will be shown if
              there are at least that many matches, even if they would all insert the same
              string.

              This  style  is tested for the default tag as well as for each tag valid for
              the current completion.  Hence the listing can be forced  only  for  certain
              types of match.

       format If  this  is  set for the descriptions tag, its value is used as a string to
              display above matches in completion lists.  The sequence '%d' in this string
              will  be  replaced with a short description of what these matches are.  This
              string  may  also  contain  the  following  sequences  to   specify   output
              attributes,  as  described  in  the section EXPANSION OF PROMPT SEQUENCES in
              zshmisc(1): '%B', '%S', '%U', '%F', '%K' and their lower case  counterparts,
              as  well  as '%{...%}'.  '%F', '%K' and '%{...%}' take arguments in the same
              form as prompt expansion.  Note that the %G sequence is  not  available;  an
              argument to '%{' should be used instead.

              The style is tested with each tag valid for the current completion before it
              is tested for the descriptions tag.  Hence different format strings  can  be
              defined for different types of match.

              Note  also  that  some  completer functions define additional '%'-sequences.
              These are described for the completer functions that make use of them.

              Some completion functions display messages that may be customised by setting
              this  style for the messages tag.  Here, the '%d' is replaced with a message
              given by the completion function.

              Finally, the format string is looked up with the warnings tag, for use  when
              no  matches  could  be  generated at all.  In this case the '%d' is replaced
              with the descriptions for  the  matches  that  were  expected  separated  by
              spaces.   The sequence '%D' is replaced with the same descriptions separated
              by newlines.

              It is possible to use printf-style field width specifiers with '%d' and sim-
              ilar  escape sequences.  This is handled by the zformat builtin command from
              the zsh/zutil module, see zshmodules(1).

       glob   This is used by the  _expand  completer.   If  it  is  set  to  'true'  (the
              default),  globbing will be attempted on the words resulting from a previous
              substitution (see the substitute style) or else the original string from the
              line.

       global If  this  is  set  to  'true' (the default), the _expand_alias completer and
              bindable command will try to expand global aliases.

       group-name
              The completion system can group different types of matches, which appear  in
              separate lists.  This style can be used to give the names of groups for par-
              ticular tags.  For example, in command position the completion system gener-
              ates  names  of builtin and external commands, names of aliases, shell func-
              tions and parameters and reserved words as possible  completions.   To  have
              the external commands and shell functions listed separately:

                     zstyle ':completion:*:*:-command-:*:commands' group-name commands
                     zstyle ':completion:*:*:-command-:*:functions' group-name functions

              As  a consequence, any match with the same tag will be displayed in the same
              group.

              If the name given is the empty string the name of the tag  for  the  matches
              will  be  used as the name of the group.  So, to have all different types of
              matches displayed separately, one can just set:

                     zstyle ':completion:*' group-name ''

              All matches for which no group name is defined will be put in a group  named
              -default-.

       group-order
              This  style  is  additional to the group-name style to specify the order for
              display of the groups defined by that style (compare tag-order, which deter-
              mines  which  completions appear at all).  The groups named are shown in the
              given order; any other groups are shown in the order defined by the  comple-
              tion function.

              For example, to have names of builtin commands, shell functions and external
              commands appear in that order when completing in command position:

                     zstyle ':completion:*:*:-command-:*' group-order \
                            builtins functions commands

       groups A list of names of UNIX groups.  If this is not set, group names  are  taken
              from the YP database or the file '/etc/group'.

       hidden If  this  is  set to true, matches for the given context will not be listed,
              although any description for the matches set with the format style  will  be
              shown.  If it is set to 'all', not even the description will be displayed.

              Note  that  the  matches will still be completed; they are just not shown in
              the list.  To avoid having matches considered  as  possible  completions  at
              all, the tag-order style can be modified as described below.

       hosts  A  list  of  names  of  hosts that should be completed.  If this is not set,
              hostnames are taken from the file '/etc/hosts'.

       hosts-ports
              This style is used by commands that need or  accept  hostnames  and  network
              ports.   The  strings in the value should be of the form 'host:port'.  Valid
              ports are determined by the presence of hostnames; multiple  ports  for  the
              same host may appear.

       ignore-line
              This  is tested for each tag valid for the current completion.  If it is set
              to 'true', none of the words that are already on the line will be considered
              as  possible completions.  If it is set to 'current', the word the cursor is
              on  will  not  be  considered  as  a   possible   completion.    The   value
              'current-shown'  is  similar  but only applies if the list of completions is
              currently shown on the screen.  Finally, if the style is set to 'other', all
              words  on the line except for the current one will be excluded from the pos-
              sible completions.

              The values 'current' and 'current-shown' are a bit like the opposite of  the
              accept-exact style:  only strings with missing characters will be completed.

              Note that you almost certainly don't want to set this to 'true'  or  'other'
              for  a  general  context  such as ':completion:*'.  This is because it would
              disallow completion of, for example, options multiple times even if the com-
              mand in question accepts the option more than once.

       ignore-parents
              The  style  is  tested without a tag by the function completing pathnames in
              order to determine whether to ignore the names of directories  already  men-
              tioned  in  the  current word, or the name of the current working directory.
              The value must include one or both of the following strings:

              parent The name of any directory whose path is already contained in the word
                     on  the line is ignored.  For example, when completing after foo/../,
                     the directory foo will not be considered a valid completion.

              pwd    The name of the current working  directory  will  not  be  completed;
                     hence, for example, completion after ../ will not use the name of the
                     current directory.

              In addition, the value may include one or both of:

              ..     Ignore the specified directories only when the word on the line  con-
                     tains the substring '../'.

              directory
                     Ignore  the  specified directories only when names of directories are
                     completed, not when completing names of files.

              Excluded values act in a similar fashion to values of  the  ignored-patterns
              style, so they can be restored to consideration by the _ignored completer.

       extra-verbose
              If  set,  the  completion  listing is more verbose at the cost of a probable
              decrease in completion speed.  Completion performance will  suffer  if  this
              style is set to 'true'.

       ignored-patterns
              A  list  of patterns; any trial completion matching one of the patterns will
              be excluded from consideration.  The _ignored completer can  appear  in  the
              list  of  completers to restore the ignored matches.  This is a more config-
              urable version of the shell parameter $fignore.

              Note that the EXTENDED_GLOB option is set during the execution of completion
              functions,  so  the characters '#', '~' and '^' have special meanings in the
              patterns.

       insert This style is used by the _all_matches completer to decide whether to insert
              the  list  of  all  matches  unconditionally  instead  of adding the list as
              another match.

       insert-ids
              When completing process IDs, for example as arguments to the kill  and  wait
              builtins  the  name of a command may be converted to the appropriate process
              ID.  A problem arises when the process name typed is not unique.  By default
              (or  if  this  style is set explicitly to 'menu') the name will be converted
              immediately to a set of possible IDs, and menu completion will be started to
              cycle through them.

              If  the  value  of the style is 'single', the shell will wait until the user
              has typed enough to make the command unique before converting the name to an
              ID;  attempts  at  completion will be unsuccessful until that point.  If the
              value is any other string, menu completion will be started when  the  string
              typed by the user is longer than the common prefix to the corresponding IDs.

       insert-tab
              If this is set to 'true', the completion system will insert a TAB  character
              (assuming   that  was  used  to  start  completion)  instead  of  performing
              completion when there is no non-blank character to the left of  the  cursor.
              If it is set to 'false', completion will be done even there.

              The  value  may  also contain the substrings 'pending' or 'pending=val'.  In
              this case, the typed character will be inserted instead of starting  comple-
              tion when there is unprocessed input pending.  If a val is given, completion
              will not be done if there are at least that many characters  of  unprocessed
              input.   This is often useful when pasting characters into a terminal.  Note
              however, that it relies on the $PENDING special parameter from  the  zsh/zle
              module being set properly which is not guaranteed on all platforms.

              The default value of this style is 'true' except for completion within vared
              builtin command where it is 'false'.

       insert-unambiguous
              This is used by the _match and _approximate  completers.   These  completers
              are  often  used  with  menu completion since the word typed may bear little
              resemblance to the final completion.  However, if this style is 'true',  the
              completer  will  start  menu completion only if it could find no unambiguous
              initial string at least as long as the original string typed by the user.

              In the case of the _approximate completer, the completer field in  the  con-
              text  will  already  have been set to one of correct-num or approximate-num,
              where num is the number of errors that were accepted.

              In the case of the _match completer, the style may also be set to the string
              'pattern'.   Then  the  pattern on the line is left unchanged if it does not
              match unambiguously.

       keep-prefix
              This style is used by the _expand completer.  If it is 'true', the completer
              will try to keep a prefix containing a tilde or parameter expansion.  Hence,
              for example, the string '~/f*' would  be  expanded  to  '~/foo'  instead  of
              '/home/user/foo'.   If the style is set to 'changed' (the default), the pre-
              fix will only be left unchanged if there  were  other  changes  between  the
              expanded words and the original word from the command line.  Any other value
              forces the prefix to be expanded unconditionally.

              The behaviour of expand when this style is true is to cause _expand to  give
              up when a single expansion with the restored prefix is the same as the orig-
              inal; hence any remaining completers may be called.

       last-prompt
              This is a more flexible form of the ALWAYS_LAST_PROMPT  option.   If  it  is
              true,  the  completion  system will try to return the cursor to the previous
              command line after displaying a completion list.  It is tested for all  tags
              valid  for the current completion, then the default tag.  The cursor will be
              moved back to the previous line if this style is 'true'  for  all  types  of
              match.   Note  that unlike the ALWAYS_LAST_PROMPT option this is independent
              of the numeric prefix argument.

       known-hosts-files
              This style should contain a list of files to search for host names  and  (if
              the  use-ip  style  is  set)  IP  addresses  in a format compatible with ssh
              known_hosts files.  If it is not set, the files /etc/ssh/ssh_known_hosts and
              ~/.ssh/known_hosts are used.

       list   This style is used by the _history_complete_word bindable command.  If it is
              set to 'true' it has no effect.  If it is set to 'false' matches will not be
              listed.   This  overrides  the  setting  of  the options controlling listing
              behaviour, in particular AUTO_LIST.  The context always starts  with  ':com-
              pletion:history-words'.

       list-colors
              If  the  zsh/complist  module is loaded, this style can be used to set color
              specifications.  This mechanism replaces  the  use  of  the  ZLS_COLORS  and
              ZLS_COLOURS parameters described in the section 'The zsh/complist Module' in
              zshmodules(1), but the syntax is the same.

              If this style is set for the default tag, the strings in the value are taken
              as  specifications  that  are to be used everywhere.  If it is set for other
              tags, the specifications are used only for matches of the type described  by
              the  tag.   For  this  to  work best, the group-name style must be set to an
              empty string.

              In addition to setting styles for specific tags, it is also possible to  use
              group  names  specified  explicitly  by the group-name tag together with the
              '(group)' syntax allowed by the ZLS_COLORS and  ZLS_COLOURS  parameters  and
              simply using the default tag.

              It  is  possible  to use any color specifications already set up for the GNU
              version of the ls command:

                     zstyle ':completion:*:default' list-colors ${(s.:.)LS_COLORS}

              The default colors are the same as  for  the  GNU  ls  command  and  can  be
              obtained by setting the style to an empty string (i.e. '').

       list-dirs-first
              This  is  used  by file completion.  If set, directories to be completed are
              listed separately from and before completion for other files, regardless  of
              tag  ordering.   In  addition,  the  tag  other-files  is  used  in place of
              all-files for the remaining files, to indicate that no directories are  pre-
              sented with that tag.

       list-grouped
              If  this  style  is  'true' (the default), the completion system will try to
              make certain completion listings more  compact  by  grouping  matches.   For
              example, options for commands that have the same description (shown when the
              verbose style is set to 'true') will appear as  a  single  entry.   However,
              menu selection can be used to cycle through all the matches.

       list-packed
              This  is  tested  for  each  tag valid in the current context as well as the
              default tag.  If it is set to 'true', the corresponding  matches  appear  in
              listings  as  if  the LIST_PACKED option were set.  If it is set to 'false',
              they are listed normally.

       list-prompt
              If this style is set for the default tag, completion lists that don't fit on
              the  screen  can be scrolled (see the description of the zsh/complist module
              in zshmodules(1)).  The value, if not the empty string,  will  be  displayed
              after  every  screenful  and  the  shell will prompt for a key press; if the
              style is set to the empty string, a default prompt will be used.

              The value may contain the escape sequences: '%l'  or  '%L',  which  will  be
              replaced  by  the  number of the last line displayed and the total number of
              lines; '%m' or '%M', the number of the  last match shown and the total  num-
              ber  of matches; and '%p' and '%P', 'Top' when at the beginning of the list,
              'Bottom' when at the end and the position shown as a percentage of the total
              length  otherwise.   In each case the form with the uppercase letter will be
              replaced by a string of fixed width, padded to the  right with spaces, while
              the lowercase form will be replaced by a variable width string.  As in other
              prompt strings, the escape sequences '%S', '%s', '%B', '%b', '%U', '%u'  for
              entering  and  leaving  the  display modes standout, bold and underline, and
              '%F', '%f', '%K', '%k' for changing the foreground  background  colour,  are
              also  available,  as  is  the  form '%{...%}' for enclosing escape sequences
              which display with zero (or, with a numeric argument, some other) width.

              After deleting this prompt the variable LISTPROMPT should be unset  for  the
              removal to take effect.

       list-rows-first
              This style is tested in the same way as the list-packed style and determines
              whether matches are  to  be  listed  in  a  rows-first  fashion  as  if  the
              LIST_ROWS_FIRST option were set.

       list-suffixes
              This style is used by the function that completes filenames.  If it is true,
              and completion is attempted on a string containing multiple partially  typed
              pathname  components,  all  ambiguous  components will be shown.  Otherwise,
              completion stops at the first ambiguous component.

       list-separator
              The value of this style is used in completion listing to separate the string
              to complete from a description when possible (e.g. when completing options).
              It defaults to '--' (two hyphens).

       local  This is for use with functions that complete URLs for which the  correspond-
              ing  files  are  available  directly from the file system.  Its value should
              consist of three strings: a hostname, the path to the default web pages  for
              the  server,  and the directory name used by a user placing web pages within
              their home area.

              For example:

                     zstyle ':completion:*' local toast \
                         /var/http/public/toast public_html

              Completion after 'http://toast/stuff/' will look for files in the  directory
              /var/http/public/toast/stuff,          while         completion        after
              'http://toast/~yousir/' will look for files in  the  directory  ~yousir/pub-
              lic_html.

       mail-directory
              If  set,  zsh  will  assume that mailbox files can be found in the directory
              specified.  It defaults to '~/Mail'.

       match-original
              This is used by the _match completer.  If it is set to only, _match will try
              to  generate matches without inserting a '*' at the cursor position.  If set
              to any other non-empty value, it will first try to generate matches  without
              inserting  the '*' and if that yields no matches, it will try again with the
              '*' inserted.  If it is unset or set to the empty string, matching will only
              be performed with the '*' inserted.

       matcher
              This  style  is tested separately for each tag valid in the current context.
              Its value is added to any match specifications  given  by  the  matcher-list
              style.  It should be in the form described in the section 'Completion Match-
              ing Control' in zshcompwid(1).

       matcher-list
              This style can be set to a list of  match  specifications  that  are  to  be
              applied  everywhere. Match specifications are described in the section 'Com-
              pletion Matching Control' in zshcompwid(1).  The completion system will  try
              them  one  after  another  for each completer selected.  For example, to try
              first simple completion and, if that generates no matches,  case-insensitive
              completion:

                     zstyle ':completion:*' matcher-list '' 'm:{a-zA-Z}={A-Za-z}'

              By default each specification replaces the previous one; however, if a spec-
              ification is prefixed with +, it is added to the existing list.  Hence it is
              possible to create increasingly general specifications without repetition:

                     zstyle ':completion:*' matcher-list '' '+m{a-z}={A-Z}' '+m{A-Z}={a-z}'

              It  is  possible  to  create  match specifications valid for particular com-
              pleters by using the third field of the context.  For example,  to  use  the
              completers  _complete and _prefix but only allow case-insensitive completion
              with _complete:

                     zstyle ':completion:*' completer _complete _prefix
                     zstyle ':completion:*:complete:*' matcher-list \
                            '' 'm:{a-zA-Z}={A-Za-z}'

              User-defined names, as explained for the  completer  style,  are  available.
              This makes it possible to try the same completer more than once with differ-
              ent match specifications each time.  For example, to try  normal  completion
              without  a match specification, then normal completion with case-insensitive
              matching, then correction, and finally partial-word completion:

                     zstyle ':completion:*' completer _complete _correct _complete:foo
                     zstyle ':completion:*:complete:*' matcher-list \
                         '' 'm:{a-zA-Z}={A-Za-z}'
                     zstyle ':completion:*:foo:*' matcher-list \
                         'm:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*'

              If the style is unset in any context  no  match  specification  is  applied.
              Note  also that some completers such as _correct and _approximate do not use
              the match specifications at all, though these completers will only  ever  be
              called once even if the matcher-list contains more than one element.

              Where multiple specifications are useful, note that the entire completion is
              done for each element of matcher-list, which can quickly reduce the  shell's
              performance.   As  a  rough  rule  of  thumb, one to three strings will give
              acceptable performance.  On the other hand, putting multiple space-separated
              values  into  the same string does not have an appreciable impact on perfor-
              mance.

              If there is no current matcher or it is empty, and the  option  NO_CASE_GLOB
              is  in effect, the matching for files is performed case-insensitively in any
              case.  However, any matcher must explicitly specify case-insensitive  match-
              ing if that is required.

       max-errors
              This  is used by the _approximate and _correct completer functions to deter-
              mine the maximum number of errors to allow.  The completer will try to  gen-
              erate  completions  by first allowing one error, then two errors, and so on,
              until either a match or matches were found or the maximum number  of  errors
              given by this style has been reached.

              If  the  value  for  this style contains the string 'numeric', the completer
              function will take any numeric argument as  the  maximum  number  of  errors
              allowed. For example, with

                     zstyle ':completion:*:approximate:::' max-errors 2 numeric

              two  errors  are allowed if no numeric argument is given, but with a numeric
              argument of six (as in 'ESC-6 TAB'), up to six errors are  accepted.   Hence
              with  a  value  of  '0  numeric', no correcting completion will be attempted
              unless a numeric argument is given.

              If the value contains the string 'not-numeric', the completer will  not  try
              to  generate corrected completions when given a numeric argument, so in this
              case the number  given  should  be  greater  than  zero.   For  example,  '2
              not-numeric'  specifies that correcting completion with two errors will usu-
              ally be performed, but if a numeric argument is given, correcting completion
              will not be performed.

              The default value for this style is '2 numeric'.

       max-matches-width
              This  style is used to determine the trade off between the width of the dis-
              play used for matches and the width used for  their  descriptions  when  the
              verbose  style  is in effect.  The value gives the number of display columns
              to reserve for the matches.  The default is half the width of the screen.

              This has the most impact when several matches have the same description  and
              so  will  be grouped together.  Increasing the style will allow more matches
              to be grouped together; decreasing it will allow more of the description  to
              be visible.

       menu   If  this  is  true in the context of any of the tags defined for the current
              completion menu completion will be used.  The value for a specific tag  will
              take precedence over that for the 'default' tag.

              If  none  of the values found in this way is true but at least one is set to
              'auto', the shell behaves as if the AUTO_MENU option is set.

              If one of the values is explicitly set to false,  menu  completion  will  be
              explicitly  turned  off,  overriding the MENU_COMPLETE option and other set-
              tings.

              In the form 'yes=num', where 'yes' may be any of  the  true  values  ('yes',
              'true',  'on'  and  '1'),  menu completion will be turned on if there are at
              least num matches.  In the form 'yes=long', menu completion will  be  turned
              on if the list does not fit on the screen.  This does not activate menu com-
              pletion if the widget normally only lists completions, but  menu  completion
              can be activated in that case with the value 'yes=long-list' (Typically, the
              value 'select=long-list' described later is more useful as it provides  con-
              trol over scrolling.)

              Similarly,  with  any of the 'false' values (as in 'no=10'), menu completion
              will not be used if there are num or more matches.

              The value of this widget also controls menu selection, as implemented by the
              zsh/complist  module.   The  following values may appear either alongside or
              instead of the values above.

              If the value contains the string 'select', menu selection  will  be  started
              unconditionally.

              In  the  form 'select=num', menu selection will only be started if there are
              at least num matches.  If the values for more than one tag provide a number,
              the smallest number is taken.

              Menu  selection  can be turned off explicitly by defining a value containing
              the string'no-select'.

              It is also possible to start menu selection only if the list of matches does
              not  fit  on  the  screen  by  using the value 'select=long'.  To start menu
              selection even if the current widget only performs listing,  use  the  value
              'select=long-list'.

              To turn on menu completion or menu selection when a there are a certain num-
              ber of matches or the list of matches does not fit on the  screen,  both  of
              'yes='  and  'select='  may be given twice, once with a number and once with
              'long' or 'long-list'.

              Finally, it is possible to activate two special  modes  of  menu  selection.
              The  word  'interactive'  in the value causes interactive mode to be entered
              immediately when menu selection is  started;  see  the  description  of  the
              zsh/complist  module in zshmodules(1) for a description of interactive mode.
              Including the string 'search' does the same for incremental search mode.  To
              select backward incremental search, include the string 'search-backward'.

       muttrc If  set,  gives the location of the mutt configuration file.  It defaults to
              '~/.muttrc'.

       numbers
              This is used with the jobs tag.  If it is 'true', the  shell  will  complete
              job  numbers  instead  of the shortest unambiguous prefix of the job command
              text.  If the value is a number, job numbers will only be used if that  many
              words  from  the  job descriptions are required to resolve ambiguities.  For
              example, if the value is '1', strings will only be used if all  jobs  differ
              in the first word on their command lines.

       old-list
              This  is  used  by  the  _oldlist completer.  If it is set to 'always', then
              standard widgets which perform listing  will  retain  the  current  list  of
              matches, however they were generated; this can be turned off explicitly with
              the value 'never', giving the behaviour without the _oldlist completer.   If
              the  style  is  unset, or any other value, then the existing list of comple-
              tions is displayed if it is not already; otherwise, the standard  completion
              list  is  generated; this is the default behaviour of _oldlist.  However, if
              there is an old list and this style contains the name of the completer func-
              tion  that generated the list, then the old list will be used even if it was
              generated by a widget which does not do listing.

              For example, suppose you type ^Xc to use  the  _correct_word  widget,  which
              generates  a  list  of  corrections for the word under the cursor.  Usually,
              typing ^D would generate a standard list of completions for the word on  the
              command  line,  and show that.  With _oldlist, it will instead show the list
              of corrections already generated.

              As another example consider the _match completer: with the  insert-unambigu-
              ous  style set to 'true' it inserts only a common prefix string, if there is
              any.  However, this may remove parts of the original pattern, so  that  fur-
              ther  completion  could  produce more matches than on the first attempt.  By
              using the _oldlist completer and setting this style to _match, the  list  of
              matches generated on the first attempt will be used again.

       old-matches
              This  is  used  by  the  _all_matches  completer to decide if an old list of
              matches should be used if one exists.  This is selected by one of the 'true'
              values  or  by the string 'only'.  If the value is 'only', _all_matches will
              only use an old list and won't have any effect on the list of  matches  cur-
              rently being generated.

              If  this  style  is set it is generally unwise to call the _all_matches com-
              pleter unconditionally.  One possible use is for either this  style  or  the
              completer style to be defined with the -e option to zstyle to make the style
              conditional.

       old-menu
              This is used by the _oldlist completer.  It  controls  how  menu  completion
              behaves  when  a  completion  has already been inserted and the user types a
              standard completion key such as TAB.  The default behaviour of  _oldlist  is
              that menu completion always continues with the existing list of completions.
              If this style is set to 'false', however, a new completion is started if the
              old  list  was  generated  by  a  different  completion command; this is the
              behaviour without the _oldlist completer.

              For example, suppose you type ^Xc to generate a  list  of  corrections,  and
              menu  completion is started in one of the usual ways.  Usually, or with this
              style set to false, typing TAB at this point would start trying to  complete
              the  line  as  it now appears.  With _oldlist, it instead continues to cycle
              through the list of corrections.

       original
              This is used by the _approximate and _correct completers to  decide  if  the
              original string should be added as a possible completion.  Normally, this is
              done only if there are at least two possible corrections, but if this  style
              is  set to 'true', it is always added.  Note that the style will be examined
              with the completer field in the context name set to correct-num or  approxi-
              mate-num, where num is the number of errors that were accepted.

       packageset
              This  style  is used when completing arguments of the Debian 'dpkg' program.
              It contains an override for the default package set  for  a  given  context.
              For example,

                     zstyle ':completion:*:complete:dpkg:option--status-1:*' \
                                    packageset avail

              causes  available  packages, rather than only installed packages, to be com-
              pleted for 'dpkg --status'.

       path   The function that completes color names uses this style with the colors tag.
              The  value  should  be  the pathname of a file containing color names in the
              format of an X11 rgb.txt file.  If the style is not set  but  this  file  is
              found in one of various standard locations it will be used as the default.

       path-completion
              This  is used by filename completion.  By default, filename completion exam-
              ines all components of a path to see if there are completions of that compo-
              nent.   For  example,  /u/b/z  can be completed to /usr/bin/zsh.  Explicitly
              setting this style to false inhibits this behaviour for path  components  up
              to the / before the cursor; this overrides the setting of accept-exact-dirs.

              Even with the style set to false, it is still possible to complete  multiple
              paths  by  setting the option COMPLETE_IN_WORD and moving the cursor back to
              the first component in the path to be completed.  For example, /u/b/z can be
              completed to /usr/bin/zsh if the cursor is after the /u.

       pine-directory
              If  set, specifies the directory containing PINE mailbox files.  There is no
              default, since recursively searching this directory is inconvenient for any-
              one who doesn't use PINE.

       ports  A  list  of  Internet service names (network ports) to complete.  If this is
              not set, service names are taken from the file '/etc/services'.

       prefix-hidden
              This is used for certain completions which share a common prefix, for  exam-
              ple command options beginning with dashes.  If it is 'true', the prefix will
              not be shown in the list of matches.

              The default value for this style is 'false'.

       prefix-needed
              This style is also relevant for matches with a common prefix.  If it is  set
              to  'true'  this  common  prefix  must  be typed by the user to generate the
              matches.

              The style is applicable to the options, signals, jobs, functions, and param-
              eters completion tags.

              For  command  options, this means that the initial '-', '+', or '--' must be
              typed explicitly before option names will be completed.

              For signals, an initial '-' is required before signal  names  will  be  com-
              pleted.

              For jobs, an initial '%' is required before job names will be completed.

              For  function  and parameter names, an initial '_' or '.' is required before
              function or parameter names starting with  those  characters  will  be  com-
              pleted.

              The  default value for this style is 'false' for function and parameter com-
              pletions, and  'true' otherwise.

       preserve-prefix
              This style is used when completing path names.  Its value should be  a  pat-
              tern  matching an initial prefix of the word to complete that should be left
              unchanged under all circumstances.  For example, on some Unices  an  initial
              '//'  (double slash) has a special meaning; setting this style to the string
              '//' will preserve it.  As another example,  setting  this  style  to  '?:/'
              under Cygwin would allow completion after 'a:/...' and so on.

       range  This  is used by the _history completer and the _history_complete_word bind-
              able command to decide which words should be completed.

              If it is a singe number, only the last N words from the history will be com-
              pleted.

              If  it is a range of the form 'max:slice', the last slice words will be com-
              pleted; then if that yields no matches, the slice words before those will be
              tried and so on.  This process stops either when at least one match was been
              found, or max words have been tried.

              The default is to complete all words from the history at once.

       regular
              This style is used by the _expand_alias completer and bindable command.   If
              set  to  'true'  (the default), regular aliases will be expanded but only in
              command position.  If it is set to 'false', regular aliases  will  never  be
              expanded.    If it is set to 'always', regular aliases will be expanded even
              if not in command position.

       rehash If this is set when completing external commands, the internal  list  (hash)
              of  commands  will be updated for each search by issuing the rehash command.
              There is a speed penalty for this which is only likely to be noticeable when
              directories in the path have slow file access.

       remote-access
              If  set  to  false,  certain commands will be prevented from making Internet
              connections to retrieve remote information.  This  includes  the  completion
              for the CVS command.

              It  is  not  always  possible to know if connections are in fact to a remote
              site, so some may be prevented unnecessarily.

       remove-all-dups
              The _history_complete_word bindable command and the _history  completer  use
              this  to decide if all duplicate matches should be removed, rather than just
              consecutive duplicates.

       select-prompt
              If this is set for the default tag, its value will be displayed during  menu
              selection  (see  the menu style above) when the completion list does not fit
              on the screen as a whole.  The same escapes as for the list-prompt style are
              understood,  except  that the numbers refer to the match or line the mark is
              on.  A default prompt is used when the value is the empty string.

       select-scroll
              This style is tested for the default tag and  determines  how  a  completion
              list is scrolled during a menu selection (see the menu style above) when the
              completion list does not fit on the screen as a whole.  If the value is  '0'
              (zero),  the  list is scrolled by half-screenfuls; if it is a positive inte-
              ger, the list is scrolled by the given number of lines; if it is a  negative
              number,  the list is scrolled by a screenful minus the absolute value of the
              given number of lines.  The default is to scroll by single lines.

       separate-sections
              This style is used with the manuals tag  when  completing  names  of  manual
              pages.  If it is 'true', entries for different sections are added separately
              using tag names of the form 'manual.X', where X is the section number.  When
              the  group-name  style is also in effect, pages from different sections will
              appear separately.  This style is also used similarly with the  words  style
              when  completing  words for the dict command. It allows words from different
              dictionary databases to be added separately.  The default for this style  is
              'false'.

       show-completer
              Tested  whenever  a  new  completer is tried.  If it is true, the completion
              system outputs a progress message in the listing area showing what completer
              is  being tried.  The message will be overwritten by any output when comple-
              tions are found and is removed after completion is finished.

       single-ignored
              This is used by the _ignored completer when there is only one match.  If its
              value  is  'show',  the single match will be displayed but not inserted.  If
              the value is 'menu', then the single match and the original string are  both
              added  as  matches  and menu completion is started, making it easy to select
              either of them.

       sort   Many completion widgets  call  _description  at  some  point  which  decides
              whether  the  matches  are  added  sorted  or unsorted (often indirectly via
              _wanted or _requested).  This style can be set  explicitly  to  one  of  the
              usual  true  or  false values as an override.  If it is not set for the con-
              text, the standard behaviour of the calling widget is used.

              The style is tested first against the full context including the tag, and if
              that fails to produce a value against the context without the tag.

              If  the calling widget explicitly requests unsorted matches, this is usually
              honoured.  However, the default (unsorted) behaviour of completion  for  the
              command history may be overridden by setting the style to true.

              In  the  _expand completer, if it is set to 'true', the expansions generated
              will always be sorted.  If it is set to 'menu', then the expansions are only
              sorted  when  they  are offered as single strings but not in the string con-
              taining all possible expansions.

       special-dirs
              Normally, the completion code will not produce the directory names  '.'  and
              '..'  as  possible completions.  If this style is set to 'true', it will add
              both '.' and '..' as possible completions; if it is set to '..',  only  '..'
              will be added.

              The  following  example sets special-dirs to '..' when the current prefix is
              empty, is a single '.', or consists only of a  path  beginning  with  '../'.
              Otherwise the value is 'false'.

                     zstyle -e ':completion:*' special-dirs \
                        '[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)'

       squeeze-slashes
              If  set  to  'true',  sequences of slashes in filename paths (for example in
              'foo//bar') will be treated as a single slash.  This is the usual  behaviour
              of  UNIX paths.  However, by default the file completion function behaves as
              if there were a '*' between the slashes.

       stop   If set to 'true', the _history_complete_word bindable command will stop once
              when  reaching  the beginning or end of the history.  Invoking _history_com-
              plete_word will then wrap around to the opposite end  of  the  history.   If
              this style is set to 'false' (the default), _history_complete_word will loop
              immediately as in a menu completion.

       strip-comments
              If set to 'true', this style causes non-essential comment text to be removed
              from  completion  matches.  Currently it is only used when completing e-mail
              addresses where it removes any display name from the addresses, cutting them
              down to plain user@host form.

       subst-globs-only
              This  is  used by the _expand completer.  If it is set to 'true', the expan-
              sion will only be used if it resulted from globbing;  hence,  if  expansions
              resulted  from  the  use  of the substitute style described below, but these
              were not further changed by globbing, the expansions will be rejected.

              The default for this style is 'false'.

       substitute
              This boolean style controls whether the _expand completer will first try  to
              expand all substitutions in the string (such as '$(...)' and '${...}').

              The default is 'true'.

       suffix This  is  used  by  the _expand completer if the word starts with a tilde or
              contains a parameter expansion.  If it is set to 'true', the word will  only
              be expanded if it doesn't have a suffix, i.e. if it is something like '~foo'
              or '$foo' rather than '~foo/' or '$foo/bar', unless that suffix itself  con-
              tains  characters  eligible  for  expansion.   The default for this style is
              'true'.

       tag-order
              This provides a mechanism for sorting how the tags available in a particular
              context will be used.

              The  values  for  the  style are sets of space-separated lists of tags.  The
              tags in each value will be tried at the same time; if no match is found, the
              next  value  is used.  (See the file-patterns style for an exception to this
              behavior.)

              For example:

                     zstyle ':completion:*:complete:-command-:*' tag-order \
                         'commands functions'

              specifies that completion in command position first offers external commands
              and  shell  functions.   Remaining  tags will be tried if no completions are
              found.

              In addition to tag names, each string in the value may take one of the  fol-
              lowing forms:

              -      If  any value consists of only a hyphen, then only the tags specified
                     in the other values are generated.  Normally all tags not  explicitly
                     selected  are  tried  last if the specified tags fail to generate any
                     matches.  This means that a single value consisting only of a  single
                     hyphen turns off completion.

              ! tags...
                     A  string  starting  with an exclamation mark specifies names of tags
                     that are not to be used.  The effect is the same as if all other pos-
                     sible tags for the context had been listed.

              tag:label ...
                     Here, tag is one of the standard tags and label is an arbitrary name.
                     Matches are generated as normal but the name label is  used  in  con-
                     texts instead of tag.  This is not useful in words starting with !.

                     If  the label starts with a hyphen, the tag is prepended to the label
                     to form the name used for lookup.  This can be used to make the  com-
                     pletion  system try a certain tag more than once, supplying different
                     style settings for each attempt; see below for an example.

              tag:label:description
                     As before, but description will replace the '%d' in the value of  the
                     format  style instead of the default description supplied by the com-
                     pletion function.  Spaces in the description must be  quoted  with  a
                     backslash.   A  '%d'  appearing  in  description is replaced with the
                     description given by the completion function.

              In any of the forms above the tag may be a pattern or  several  patterns  in
              the  form  '{pat1,pat2...}'.   In  this  case all matching tags will be used
              except for any given explicitly in the same string.

              One use of these features is to try one tag more than  once,  setting  other
              styles  differently  on  each  attempt,  but still to use all the other tags
              without having to repeat them all.  For example, to make completion of func-
              tion  names in command position ignore all the completion functions starting
              with an underscore the first time completion is tried:

                     zstyle ':completion:*:*:-command-:*' tag-order \
                         'functions:-non-comp *' functions
                     zstyle ':completion:*:functions-non-comp' ignored-patterns '_*'

              On the first attempt, all tags will be offered but the functions tag will be
              replaced  by functions-non-comp.  The ignored-patterns style is set for this
              tag to exclude functions starting with  an  underscore.   If  there  are  no
              matches,  the  second  value  of the tag-order style is used which completes
              functions using the default tag, this time presumably including all function
              names.

              The matches for one tag can be split into different groups.  For example:

                     zstyle ':completion:*' tag-order \
                         'options:-long:long\ options
                          options:-short:short\ options
                          options:-single-letter:single\ letter\ options'

                     zstyle ':completion:*:options-long' ignored-patterns '[-+](|-|[^-]*)'
                     zstyle ':completion:*:options-short' ignored-patterns '--*' '[-+]?'
                     zstyle ':completion:*:options-single-letter' ignored-patterns '???*'

              With  the group-names style set, options beginning with '--', options begin-
              ning with a single '-' or '+' but containing multiple characters,  and  sin-
              gle-letter  options  will  be  displayed  in  separate groups with different
              descriptions.

              Another use of patterns is to try multiple match  specifications  one  after
              another.   The matcher-list style offers something similar, but it is tested
              very early in the completion system and hence can't be set for  single  com-
              mands  nor for more specific contexts.  Here is how to try normal completion
              without any match specification and, if that generates no matches, try again
              with  case-insensitive  matching, restricting the effect to arguments of the
              command foo:

                     zstyle ':completion:*:*:foo:*' tag-order '*' '*:-case'
                     zstyle ':completion:*-case' matcher 'm:{a-z}={A-Z}'

              First, all the tags offered when completing after foo are  tried  using  the
              normal  tag  name.   If  that  generates  no  matches,  the  second value of
              tag-order is used, which tries all tags again except that this time each has
              -case  appended to its name for lookup of styles.  Hence this time the value
              for the matcher style from the second call to zstyle in the example is  used
              to make completion case-insensitive.

              It is possible to use the -e option of the zstyle builtin command to specify
              conditions for the use of particular tags.  For example:

                     zstyle -e '*:-command-:*' tag-order '
                         if [[ -n $PREFIX$SUFFIX ]]; then
                           reply=( )
                         else
                           reply=( - )
                         fi'

              Completion in command position will be attempted only if the string typed so
              far  is  not  empty.  This is tested using the PREFIX special parameter; see
              zshcompwid for a description of parameters which are special inside  comple-
              tion  widgets.   Setting  reply  to  an  empty  array  provides  the default
              behaviour of trying all tags at once; setting it to an array containing only
              a hyphen disables the use of all tags and hence of all completions.

              If  no  tag-order  style  has  been  defined  for  a  context,  the  strings
              '(|*-)argument-* (|*-)option-* values' and 'options' plus all  tags  offered
              by the completion function will be used to provide a sensible default behav-
              ior that causes arguments (whether normal command arguments or arguments  of
              options) to be completed before option names for most commands.

       urls   This is used together with the urls tag by functions completing URLs.

              If  the  value  consists of more than one string, or if the only string does
              not name a file or directory, the strings are used as the URLs to  complete.

              If the value contains only one string which is the name of a normal file the
              URLs are taken from that file (where the URLs  may  be  separated  by  white
              space or newlines).

              Finally,  if  the  only string in the value names a directory, the directory
              hierarchy rooted at this directory gives the  completions.   The  top  level
              directory  should  be  the file access method, such as 'http', 'ftp', 'book-
              mark' and so on.  In many cases the next level  of  directories  will  be  a
              filename.  The directory hierarchy can descend as deep as necessary.

              For example,

                     zstyle ':completion:*' urls ~/.urls
                     mkdir -p ~/.urls/ftp/ftp.zsh.org/pub

              allows  completion  of  all  the components of the URL ftp://ftp.zsh.org/pub
              after suitable commands such as 'netscape' or 'lynx'.  Note,  however,  that
              access  methods and files are completed separately, so if the hosts style is
              set hosts can be completed without reference to the urls style.

              See the description in the function _urls itself for more information  (e.g.
              'more $^fpath/_urls(N)').

       use-cache
              If  this  is  set, the completion caching layer is activated for any comple-
              tions  which  use   it   (via   the   _store_cache,   _retrieve_cache,   and
              _cache_invalid  functions).  The directory containing the cache files can be
              changed with the cache-path style.

       use-compctl
              If this style is set to a string not equal to false, 0,  no,  and  off,  the
              completion  system  may  use  any completion specifications defined with the
              compctl builtin command.  If the style is unset, this is done  only  if  the
              zsh/compctl  module  is  loaded.   The string may also contain the substring
              'first' to use completions defined with  'compctl  -T',  and  the  substring
              'default' to use the completion defined with 'compctl -D'.

              Note that this is only intended to smooth the transition from compctl to the
              new completion system and may disappear in the future.

              Note also that the definitions from compctl will only be used if there is no
              specific  completion  function for the command in question.  For example, if
              there is a function _foo to complete arguments to the command  foo,  compctl
              will  never  be invoked for foo.  However, the compctl version will be tried
              if foo only uses default completion.

       use-ip By default,  the  function  _hosts  that  completes  host  names  strips  IP
              addresses  from  entries read from host databases such as NIS and ssh files.
              If this style is true, the corresponding IP addresses can  be  completed  as
              well.   This  style  is not use in any context where the hosts style is set;
              note also it must be set before the cache of host names is generated  (typi-
              cally the first completion attempt).

       users  This  may  be  set to a list of usernames to be completed.  If it is not set
              all usernames will be completed.  Note that if it is set only that  list  of
              users  will be completed; this is because on some systems querying all users
              can take a prohibitive amount of time.

       users-hosts
              The values of this style should be of the form 'user@host'  or  'user:host'.
              It  is used for commands that need pairs of user- and hostnames.  These com-
              mands will complete usernames from this style (only), and will restrict sub-
              sequent  hostname  completion  to  hosts paired with that user in one of the
              values of the style.

              It is possible to group values for sets of commands  which  allow  a  remote
              login,  such  as  rlogin  and ssh, by using the my-accounts tag.  Similarly,
              values for sets of commands which usually refer to  the  accounts  of  other
              people,  such as talk and finger, can be grouped by using the other-accounts
              tag.  More ambivalent commands may use the accounts tag.

       users-hosts-ports
              Like users-hosts but used for commands like telnet and containing strings of
              the form 'user@host:port'.

       verbose
              If  set,  as  it  is by default, the completion listing is more verbose.  In
              particular many commands show descriptions for  options  if  this  style  is
              'true'.

       word   This is used by the _list completer, which prevents the insertion of comple-
              tions until a second completion attempt when the line has not changed.   The
              normal  way  of finding out if the line has changed is to compare its entire
              contents between the two occasions.  If this style is true,  the  comparison
              is  instead performed only on the current word.  Hence if completion is per-
              formed on another word with  the  same  contents,  completion  will  not  be
              delayed.


CONTROL FUNCTIONS
       The  initialization script compinit redefines all the widgets which perform comple-
       tion to call the supplied widget function _main_complete.  This function acts as  a
       wrapper  calling  the  so-called  'completer'  functions that generate matches.  If
       _main_complete is called with arguments, these are taken as the names of  completer
       functions  to  be called in the order given.  If no arguments are given, the set of
       functions to try is taken from the completer style.  For  example,  to  use  normal
       completion and correction if that doesn't generate any matches:

              zstyle ':completion:*' completer _complete _correct

       after  calling  compinit. The default value for this style is '_complete _ignored',
       i.e. normally only ordinary completion is tried,  first  with  the  effect  of  the
       ignored-patterns  style  and then without it.  The _main_complete function uses the
       return status of the completer functions to decide if other  completers  should  be
       called.   If  the  return  status  is  zero,  no other completers are tried and the
       _main_complete function returns.

       If the first argument to _main_complete is a single hyphen, the arguments will  not
       be  taken as names of completers.  Instead, the second argument gives a name to use
       in the completer field of the context and the other arguments give a  command  name
       and arguments to call to generate the matches.

       The following completer functions are contained in the distribution, although users
       may write their own.  Note that in contexts the leading underscore is stripped, for
       example basic completion is performed in the context ':completion::complete:...'.

       _all_matches
              This  completer can be used to add a string consisting of all other matches.
              As it influences later completers it must appear as the first  completer  in
              the  list.   The  list of all matches is affected by the avoid-completer and
              old-matches styles described above.

              It may be useful to use  the  _generic  function  described  below  to  bind
              _all_matches to its own keystroke, for example:

                     zle -C all-matches complete-word _generic
                     bindkey '^Xa' all-matches
                     zstyle ':completion:all-matches:*' old-matches only
                     zstyle ':completion:all-matches::::' completer _all_matches

              Note  that  this  does not generate completions by itself:  first use any of
              the standard ways of generating a list of completions, then use ^Xa to  show
              all matches.  It is possible instead to add a standard completer to the list
              and request that the list of all matches should be directly inserted:

                     zstyle ':completion:all-matches::::' completer _all_matches _complete
                     zstyle ':completion:all-matches:*' insert true

              In this case the old-matches style should not be set.

       _approximate
              This is similar to the basic _complete completer but allows the  completions
              to  undergo  corrections.   The maximum number of errors can be specified by
              the max-errors style; see the description of approximate  matching  in  zsh-
              expn(1)  for  how  errors are counted.  Normally this completer will only be
              tried after the normal _complete completer:

                     zstyle ':completion:*' completer _complete _approximate

              This will give correcting completion if and only if normal completion yields
              no  possible  completions.   When  corrected completions are found, the com-
              pleter will normally start menu completion allowing  you  to  cycle  through
              these strings.

              This  completer  uses  the tags corrections and original when generating the
              possible corrections and the original string.  The format style for the for-
              mer  may  contain  the  additional  sequences  '%e'  and  '%o' which will be
              replaced by the number of errors accepted to generate  the  corrections  and
              the original string, respectively.

              The completer progressively increases the number of errors allowed up to the
              limit by the max-errors style, hence if  a  completion  is  found  with  one
              error, no completions with two errors will be shown, and so on.  It modifies
              the completer name in the context to indicate the  number  of  errors  being
              tried: on the first try the completer field contains 'approximate-1', on the
              second try 'approximate-2', and so on.

              When _approximate is called from another function, the number of  errors  to
              accept may be passed with the -a option.  The argument is in the same format
              as the max-errors style, all in one string.

              Note that this completer (and the _correct completer mentioned below) can be
              quite  expensive  to  call,  especially  when  a  large number of errors are
              allowed.  One way to avoid this is to set up the completer style  using  the
              -e option to zstyle so that some completers are only used when completion is
              attempted a second time on the same string, e.g.:

                     zstyle -e ':completion:*' completer '
                       if [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
                         _last_try="$HISTNO$BUFFER$CURSOR"
                         reply=(_complete _match _prefix)
                       else
                         reply=(_ignored _correct _approximate)
                       fi'

              This uses the HISTNO parameter and the BUFFER and CURSOR special  parameters
              that are available inside zle and completion widgets to find out if the com-
              mand line hasn't changed since the last time  completion  was  tried.   Only
              then are the _ignored, _correct and _approximate completers called.

       _complete
              This  completer  generates  all  possible completions in a context-sensitive
              manner, i.e. using the settings defined with the compdef function  explained
              above  and  the  current settings of all special parameters.  This gives the
              normal completion behaviour.

              To complete arguments of commands, _complete uses the utility function _nor-
              mal, which is in turn responsible for finding the particular function; it is
              described below.  Various contexts of the form -context- are handled specif-
              ically.  These are all mentioned above as possible arguments to the #compdef
              tag.

              Before trying to find a function for a specific context, _complete checks if
              the  parameter  'compcontext' is set. Setting 'compcontext' allows the usual
              completion dispatching to be overridden which is useful in places such as  a
              function  that  uses vared for input. If it is set to an array, the elements
              are taken to be the possible matches which will be completed using  the  tag
              'values'  and the description 'value'. If it is set to an associative array,
              the keys are used as the possible completions and the values (if  non-empty)
              are  used  as  descriptions  for  the matches.  If 'compcontext' is set to a
              string containing colons, it should be of the form  'tag:descr:action'.   In
              this  case  the  tag  and  descr give the tag and description to use and the
              action indicates what should be completed in one of the  forms  accepted  by
              the _arguments utility function described below.

              Finally,  if  'compcontext'  is set to a string without colons, the value is
              taken as the name of the context to use and the function  defined  for  that
              context  will be called.  For this purpose, there is a special context named
              -command-line- that completes whole command lines (commands and their  argu-
              ments).  This is not used by the completion system itself but is nonetheless
              handled when explicitly called.

       _correct
              Generate corrections, but not completions, for the  current  word;  this  is
              similar to _approximate but will not allow any number of extra characters at
              the cursor as that completer does.  The effect is similar to spell-checking.
              It  is based on _approximate, but the completer field in the context name is
              correct.

              For example, with:

                     zstyle ':completion:::::' completer _complete _correct _approximate
                     zstyle ':completion:*:correct:::' max-errors 2 not-numeric
                     zstyle ':completion:*:approximate:::' max-errors 3 numeric

              correction will accept up to two errors.  If a numeric  argument  is  given,
              correction  will  not  be  performed, but correcting completion will be, and
              will accept as many errors as given by  the  numeric  argument.   Without  a
              numeric  argument,  first  correction and then correcting completion will be
              tried, with the first one accepting two errors and the second one  accepting
              three errors.

              When _correct is called as a function, the number of errors to accept may be
              given following the -a option.  The argument is in the same form a values to
              the accept style, all in one string.

              This completer function is intended to be used without the _approximate com-
              pleter or, as in the example, just before it.  Using it after the  _approxi-
              mate completer is useless since _approximate will at least generate the cor-
              rected strings generated by the _correct completer -- and probably more.

       _expand
              This completer function does not  really  perform  completion,  but  instead
              checks  if the word on the command line is eligible for expansion and, if it
              is, gives detailed control over how this expansion is  done.   For  this  to
              happen,  the  completion  system needs to be invoked with complete-word, not
              expand-or-complete (the default binding for TAB), as  otherwise  the  string
              will  be  expanded  by  the shell's internal mechanism before the completion
              system is started.  Note also this completer should  be  called  before  the
              _complete completer function.

              The  tags  used when generating expansions are all-expansions for the string
              containing all possible expansions,  expansions  when  adding  the  possible
              expansions  as  single  matches and original when adding the original string
              from the line.  The order in which these strings are generated, if  at  all,
              can be controlled by the group-order and tag-order styles, as usual.

              The  format  string  for  all-expansions  and for expansions may contain the
              sequence '%o' which will be replaced by the original string from the line.

              The kind of expansion to be tried is controlled by the substitute, glob  and
              subst-globs-only styles.

              It is also possible to call _expand as a function, in which case the differ-
              ent modes may be selected with options: -s for substitute, -g for  glob  and
              -o for subst-globs-only.

       _expand_alias
              If  the  word the cursor is on is an alias, it is expanded and no other com-
              pleters are called.  The types of aliases which are to be  expanded  can  be
              controlled with the styles regular, global and disabled.

              This  function  is  also  a bindable command, see the section 'Bindable Com-
              mands' below.

       _history
              Complete words from the shell's command  history.   This  completer  can  be
              controlled  by the remove-all-dups, and sort styles as for the _history_com-
              plete_word bindable command, see the section 'Bindable Commands'  below  and
              the section 'Completion System Configuration' above.

       _ignored
              The  ignored-patterns  style can be set to a list of patterns which are com-
              pared against possible completions; matching ones are  removed.   With  this
              completer  those  matches can be reinstated, as if no ignored-patterns style
              were set.  The completer actually generates its own list of  matches;  which
              completers are invoked is determined in the same way as for the _prefix com-
              pleter.  The single-ignored style is also available as described above.

       _list  This completer allows the insertion of matches to be delayed  until  comple-
              tion  is attempted a second time without the word on the line being changed.
              On the first attempt, only the  list  of  matches  will  be  shown.   It  is
              affected  by the styles condition and word, see the section 'Completion Sys-
              tem Configuration' above.

       _match This completer is intended to be used after  the  _complete  completer.   It
              behaves  similarly  but  the  string on the command line may be a pattern to
              match against trial completions.  This gives the effect of the GLOB_COMPLETE
              option.

              Normally  completion  will be performed by taking the pattern from the line,
              inserting a '*' at the cursor position and comparing the  resulting  pattern
              with  the  possible  completions  generated.   This can be modified with the
              match-original style described above.

              The generated matches will be  offered  in  a  menu  completion  unless  the
              insert-unambiguous  style  is  set  to 'true'; see the description above for
              other options for this style.

              Note that matcher specifications defined globally or used by the  completion
              functions (the styles matcher-list and matcher) will not be used.

       _menu  This  completer was written as simple example function to show how menu com-
              pletion can be enabled in shell code. However, it has the notable effect  of
              disabling menu selection which can be useful with _generic based widgets. It
              should be used as the first completer in the list.  Note that this is  inde-
              pendent  of  the  setting of the MENU_COMPLETE option and does not work with
              the  other  menu  completion  widgets  such  as  reverse-menu-complete,   or
              accept-and-menu-complete.

       _oldlist
              This  completer  controls  how  the  standard completion widgets behave when
              there is an existing list of completions which may have been generated by  a
              special  completion (i.e. a separately-bound completion command).  It allows
              the ordinary completion keys to continue to use the list of completions thus
              generated,  instead  of  producing a new list of ordinary contextual comple-
              tions.  It should appear in the list of completers before any of the widgets
              which  generate matches.  It uses two styles: old-list and old-menu, see the
              section 'Completion System Configuration' above.

       _prefix
              This completer can be used to try completion  with  the  suffix  (everything
              after  the  cursor) ignored.  In other words, the suffix will not be consid-
              ered to be part of the word to complete.   The  effect  is  similar  to  the
              expand-or-complete-prefix command.

              The  completer  style  is  used  to  decide which other completers are to be
              called to generate matches.  If this style is unset, the list of  completers
              set  for  the current context is used -- except, of course, the _prefix com-
              pleter itself.  Furthermore, if this completer appears more than once in the
              list of completers only those completers not already tried by the last invo-
              cation of _prefix will be called.

              For example, consider this global completer style:

                     zstyle ':completion:*' completer \
                         _complete _prefix _correct _prefix:foo

              Here, the _prefix completer tries normal completion but ignoring the suffix.
              If that doesn't generate any matches, and neither does the call to the _cor-
              rect completer after it, _prefix will be called a second time and, now  only
              trying  correction  with  the  suffix ignored.  On the second invocation the
              completer part of the context appears as 'foo'.

              To use _prefix as the last resort and try only normal completion when it  is
              invoked:

                     zstyle ':completion:*' completer _complete ... _prefix
                     zstyle ':completion::prefix:*' completer _complete

              The  add-space style is also respected.  If it is set to 'true' then _prefix
              will insert a space between the matches generated (if any) and the suffix.

              Note that this completer is only useful if the  COMPLETE_IN_WORD  option  is
              set;  otherwise,  the  cursor  will  be moved to the end of the current word
              before the completion code is called and hence there will be no suffix.

       _user_expand
              This completer behaves similarly to the _expand completer but  instead  per-
              forms  expansions  defined  by  users.  The styles add-space and sort styles
              specific to the _expand completer are usable with _user_expand  in  addition
              to  other  styles  handled more generally by the completion system.  The tag
              all-expansions is also available.

              The expansion depends on the array style user-expand being defined  for  the
              current  context;  remember that the context for completers is less specific
              than that for contextual completion as the full context  has  not  yet  been
              determined.  Elements of the array may have one of the following forms:
              $hash    hash  is the name of an associative array.  Note this is not a full
                     parameter expression, merely a $, suitably quoted to prevent  immedi-
                     ate  expansion, followed by the name of an associative array.  If the
                     trial expansion word matches a key in hash, the  resulting  expansion
                     is the corresponding value.
              _func    _func  is the name of a shell function whose name must begin with _
                     but is not otherwise special to the completion system.  The  function
                     is  called  with the trial word as an argument.  If the word is to be
                     expanded, the function should set the array reply to a list of expan-
                     sions.  The return status of the function is irrelevant.


BINDABLE COMMANDS
       In  addition  to  the context-dependent completions provided, which are expected to
       work in an intuitively obvious way, there are a few  widgets  implementing  special
       behaviour  which can be bound separately to keys.  The following is a list of these
       and their default bindings.

       _bash_completions
              This  function   is   used   by   two   widgets,   _bash_complete-word   and
              _bash_list-choices.   It  exists  to  provide  compatibility with completion
              bindings in bash.  The last character of the binding determines what is com-
              pleted:  '!',  command  names;  '$', environment variables; '@', host names;
              '/', file names; '~' user names.  In bash,  the  binding  preceded  by  '\e'
              gives  completion,  and  preceded  by  '^X' lists options.  As some of these
              bindings clash with standard zsh bindings, only '\e~' and '^X~' are bound by
              default.   To  add  the  rest, the following should be added to .zshrc after
              compinit has been run:

                     for key in '!' '$' '@' '/' '~'; do
                       bindkey "\e$key" _bash_complete-word
                       bindkey "^X$key" _bash_list-choices
                     done

              This includes the bindings for '~' in case they were already bound to  some-
              thing else; the completion code does not override user bindings.

       _correct_filename (^XC)
              Correct  the  filename path at the cursor position.  Allows up to six errors
              in the name.  Can also be called with an  argument  to  correct  a  filename
              path, independently of zle; the correction is printed on standard output.

       _correct_word (^Xc)
              Performs  correction of the current argument using the usual contextual com-
              pletions as possible choices. This stores the string 'correct-word'  in  the
              function field of the context name and then calls the _correct completer.

       _expand_alias (^Xa)
              This  function  can  be  used  as a completer and as a bindable command.  It
              expands the word the cursor is on if it is an alias.   The  types  of  alias
              expanded can be controlled with the styles regular, global and disabled.

              When  used as a bindable command there is one additional feature that can be
              selected by setting the complete style to 'true'.  In this case, if the word
              is  not  the name of an alias, _expand_alias tries to complete the word to a
              full alias name without expanding it.  It leaves the cursor  directly  after
              the  completed word so that invoking _expand_alias once more will expand the
              now-complete alias name.

       _expand_word (^Xe)
              Performs  expansion  on  the  current  word:   equivalent  to  the  standard
              expand-word  command,  but  using the _expand completer.  Before calling it,
              the function field of the context is set to 'expand-word'.

       _generic
              This function is not defined as a widget and not bound by default.  However,
              it can be used to define a widget and will then store the name of the widget
              in the function field of the context and call the completion  system.   This
              allows  custom completion widgets with their own set of style settings to be
              defined easily.  For example, to define a widget that performs  normal  com-
              pletion and starts menu selection:

                     zle -C foo complete-word _generic
                     bindkey '...' foo
                     zstyle ':completion:foo:*' menu yes select=1

              Note  in  particular  that the completer style may be set for the context in
              order to change the set of functions used to generate possible matches.   If
              _generic  is  called  with arguments, those are passed through to _main_com-
              plete as the list of completers in place of those defined by  the  completer
              style.

       _history_complete_word (\e/)
              Complete  words  from  the  shell's  command  history.  This  uses the list,
              remove-all-dups, sort, and stop styles.

       _most_recent_file (^Xm)
              Complete the name of the most recently modified file matching the pattern on
              the  command line (which may be blank).  If given a numeric argument N, com-
              plete the Nth most recently modified file.  Note the completion, if any,  is
              always unique.

       _next_tags (^Xn)
              This command alters the set of matches used to that for the next tag, or set
              of tags, either as given by the tag-order style or as set by default;  these
              matches  would  otherwise  not  be available.  Successive invocations of the
              command cycle through all possible sets of tags.

       _read_comp (^X^R)
              Prompt the user for a string, and use that to perform completion on the cur-
              rent  word.  There are two possibilities for the string.  First, it can be a
              set of words beginning '_', for example '_files -/', in which case the func-
              tion  with  any arguments will be called to generate the completions.  Unam-
              biguous parts of the function name will be completed  automatically  (normal
              completion is not available at this point) until a space is typed.

              Second, any other string will be passed as a set of arguments to compadd and
              should hence be an expression specifying what should be completed.

              A very restricted set of editing commands  is  available  when  reading  the
              string:   'DEL'  and  '^H' delete the last character; '^U' deletes the line,
              and '^C' and '^G' abort the function, while 'RET'  accepts  the  completion.
              Note  the  string  is  used verbatim as a command line, so arguments must be
              quoted in accordance with standard shell rules.

              Once a string has been read, the next call to _read_comp will use the exist-
              ing  string instead of reading a new one.  To force a new string to be read,
              call _read_comp with a numeric argument.

       _complete_debug (^X?)
              This widget performs ordinary completion, but captures in a temporary file a
              trace of the shell commands executed by the completion system.  Each comple-
              tion attempt gets its own file.  A command to view each of  these  files  is
              pushed onto the editor buffer stack.

       _complete_help (^Xh)
              This  widget displays information about the context names, the tags, and the
              completion functions used when completing at the current cursor position. If
              given  a  numeric argument other than 1 (as in 'ESC-2 ^Xh'), then the styles
              used and the contexts for which they are used will be shown, too.

              Note that the information about styles may be incomplete; it depends on  the
              information available from the completion functions called, which in turn is
              determined by the user's own styles and other settings.

       _complete_help_generic
              Unlike other commands listed here, this must be created as a normal ZLE wid-
              get rather than a completion widget (i.e. with zle -N).  It is used for gen-
              erating help with a widget bound to the _generic widget  that  is  described
              above.

              If  this  widget  is  created  using  the  name of the function, as it is by
              default, then when executed it will read a key sequence.  This  is  expected
              to  be  bound to a call to a completion function that uses the _generic wid-
              get.  That widget will be executed, and information  provided  in  the  same
              format that the _complete_help widget displays for contextual completion.

              If the widget's name contains debug, for example if it is created as 'zle -N
              _complete_debug_generic _complete_help_generic', it will  read  and  execute
              the  keystring  for  a generic widget as before, but then generate debugging
              information as done by _complete_debug for contextual completion.

              If the widget's name contains noread, it  will  not  read  a  keystring  but
              instead  arrange that the next use of a generic widget run in the same shell
              will have the effect as described above.

              The widget works by setting  the  shell  parameter  ZSH_TRACE_GENERIC_WIDGET
              which  is  read  by  _generic.   Unsetting the parameter cancels any pending
              effect of the noread form.

              For example, after executing the following:

                     zle -N _complete_debug_generic _complete_help_generic
                     bindkey '^x:' _complete_debug_generic

              typing 'C-x :' followed by the key sequence for a generic widget will  cause
              trace output for that widget to be saved to a file.

       _complete_tag (^Xt)
              This  widget  completes symbol tags created by the etags or ctags programmes
              (note there is no connection with the completion system's tags) stored in  a
              file  TAGS,  in  the format used by etags, or tags, in the format created by
              ctags.  It will look back up the path hierarchy for the first occurrence  of
              either file; if both exist, the file TAGS is preferred.  You can specify the
              full path to a TAGS or tags file  by  setting  the  parameter  $TAGSFILE  or
              $tagsfile  respectively.   The  corresponding completion tags used are etags
              and vtags, after emacs and vi respectively.


UTILITY FUNCTIONS
       Descriptions follow for utility functions that may be useful when  writing  comple-
       tion functions.  If functions are installed in subdirectories, most of these reside
       in the Base subdirectory.  Like the example functions for commands in the distribu-
       tion, the utility functions generating matches all follow the convention of return-
       ing status zero if they generated completions and non-zero if no  matching  comple-
       tions could be added.

       Two  more features are offered by the _main_complete function.  The arrays comppre-
       funcs and comppostfuncs may contain names of functions that are to be called  imme-
       diately  before or after completion has been tried.  A function will only be called
       once unless it explicitly reinserts itself into the array.

       _all_labels [ -x ] [ -12VJ ] tag name descr [ command args ... ]
              This is a convenient interface to the _next_label function below, implement-
              ing  the  loop  shown in the _next_label example.  The command and its argu-
              ments are called to generate the matches.  The options stored in the parame-
              ter name will automatically be inserted into the args passed to the command.
              Normally, they are put directly after the command, but if one of the args is
              a  single  hyphen, they are inserted directly before that.  If the hyphen is
              the last argument, it will be removed from the argument list before the com-
              mand  is  called.   This  allows  _all_labels to be used in almost all cases
              where the matches can be generated by a single call to the  compadd  builtin
              command or by a call to one of the utility functions.

              For example:

                     local expl
                     ...
                     if _requested foo; then
                       ...
                       _all_labels foo expl '...' compadd ... - $matches
                     fi

              Will  complete  the  strings  from the matches parameter, using compadd with
              additional options which  will  take  precedence  over  those  generated  by
              _all_labels.

       _alternative [ -O name ] [ -C name ] spec ...
              This  function  is useful in simple cases where multiple tags are available.
              Essentially it implements a loop like the one described for the _tags  func-
              tion below.

              The  tags  to  use  and  the  action  to  perform  if a tag is requested are
              described using the specs which are of the  form:  'tag:descr:action'.   The
              tags are offered using _tags and if the tag is requested, the action is exe-
              cuted with the given description descr.  The actions are those  accepted  by
              the  _arguments  function  (described  below),  excluding  the '->state' and
              '=...' forms.

              For example, the action may be a simple function call:

                     _alternative \
                         'users:user:_users' \
                         'hosts:host:_hosts'

              offers usernames and hostnames as possible matches, generated by the  _users
              and _hosts functions respectively.

              Like  _arguments,  this  function  uses  _all_labels to execute the actions,
              which will loop over all sets of tags.  Special handling is only required if
              there  is an additional valid tag, for example inside a function called from
              _alternative.

              The option '-O name' is used in the same way as by the _arguments  function.
              In  other  words,  the  elements of the name array will be passed to compadd
              when executing an action.

              Like _tags this function supports the -C option to give a different name for
              the argument context field.

       _arguments [ -nswWACRS ] [ -O name ] [ -M matchspec ] [ : ] spec ...
              This  function  can  be used to give a complete specification for completion
              for a command whose arguments follow standard UNIX option and argument  con-
              ventions.   The following forms specify individual sets of options and argu-
              ments; to avoid ambiguity, these may be separated from the options to _argu-
              ments  itself  by  a  single colon.  Options to _arguments itself must be in
              separate words, i.e. -s -w, not -sw.

              With the option -n, _arguments sets the parameter NORMARG to the position of
              the  first  normal argument in the $words array, i.e. the position after the
              end of the options.  If that argument has not been reached, NORMARG  is  set
              to  -1.   The  caller  should  declare 'integer NORMARG' if the -n option is
              passed; otherwise the parameter is not used.

              n:message:action
              n::message:action
                     This describes the n'th normal argument.  The message will be printed
                     above the matches generated and the action indicates what can be com-
                     pleted in this position (see below).  If there are two colons  before
                     the  message  the argument is optional.  If the message contains only
                     white space, nothing will be printed above  the  matches  unless  the
                     action adds an explanation string itself.

              :message:action
              ::message:action
                     Similar,  but  describes the next argument, whatever number that hap-
                     pens to be.  If all arguments are specified in this form in the  cor-
                     rect order the numbers are unnecessary.

              *:message:action
              *::message:action
              *:::message:action
                     This describes how arguments (usually non-option arguments, those not
                     beginning with - or +) are to be completed when neither of the  first
                     two  forms was provided.  Any number of arguments can be completed in
                     this fashion.

                     With two colons before the message, the words special array  and  the
                     CURRENT  special  parameter  are modified to refer only to the normal
                     arguments when the action  is  executed  or  evaluated.   With  three
                     colons before the message they are modified to refer only to the nor-
                     mal arguments covered by this description.

              optspec
              optspec:...
                     This describes an option.  The colon indicates handling  for  one  or
                     more  arguments  to  the  option; if it is not present, the option is
                     assumed to take no arguments.

                     By default, options are multi-character name, one '-word' per option.
                     With  -s, options may be single characters, with more than one option
                     per word, although words starting with two hyphens, such  as  '--pre-
                     fix',  are  still considered complete option names.  This is suitable
                     for standard GNU options.

                     The combination of -s with -w allows single-letter options to be com-
                     bined  in a single word even if one or more of the options take argu-
                     ments.  For example, if -a takes an argument, with  no  -s  '-ab'  is
                     considered  as  a single (unhandled) option; with -s -ab is an option
                     with the argument 'b'; with both -s and -w, -ab may be the option  -a
                     and the option -b with arguments still to come.

                     The option -W takes this a stage further:  it is possible to complete
                     single-letter options even after an argument that occurs in the  same
                     word.   However,  it  depends on the action performed whether options
                     will really be completed at this point.   For  more  control,  use  a
                     utility function like _guard as part of the action.

                     The following forms are available for the initial optspec, whether or
                     not the option has arguments.

                     *optspec
                             Here optspec is one of the remaining forms below.  This indi-
                             cates  the  following  optspec may be repeated.  Otherwise if
                             the corresponding option is already present  on  the  command
                             line  to the left of the cursor it will not be offered again.

                     -optname
                     +optname
                             In the simplest form the optspec  is  just  the  option  name
                             beginning  with  a minus or a plus sign, such as '-foo'.  The
                             first argument for the option (if any) must follow as a sepa-
                             rate word directly after the option.

                             Either  of '-+optname' and '+-optname' can be used to specify
                             that -optname and +optname are both valid.

                             In all the remaining forms, the leading '-' may  be  replaced
                             by or paired with '+' in this way.

                     -optname-
                             The first argument of the option must come directly after the
                             option name in the same word.  For example, '-foo-:...' spec-
                             ifies  that  the completed option and argument will look like
                             '-fooarg'.

                     -optname+
                             The first argument may appear immediately  after  optname  in
                             the  same  word,  or  may appear as a separate word after the
                             option.  For example, '-foo+:...'  specifies  that  the  com-
                             pleted option and argument will look like either '-fooarg' or
                             '-foo arg'.

                     -optname=
                             The argument may appear as the next word, or in same word  as
                             the  option  name provided that it is separated from it by an
                             equals sign, for example '-foo=arg' or '-foo arg'.

                     -optname=-
                             The argument to the option must appear after an  equals  sign
                             in  the same word, and may not be given in the next argument.

                     optspec[explanation]
                             An explanation string may be appended to any of the preceding
                             forms of optspec by enclosing it in brackets, as in '-q[query
                             operation]'.

                             The verbose style is used to decide whether  the  explanation
                             strings  are  displayed with the option in a completion list-
                             ing.

                             If  no  bracketed  explanation  string  is  given   but   the
                             auto-description  style  is  set  and  only  one  argument is
                             described for this optspec, the value of the  style  is  dis-
                             played,  with  any  appearance  of  the  sequence  '%d' in it
                             replaced by the message of the first optarg that follows  the
                             optspec; see below.

              It  is  possible  for  options with a literal '+' or '=' to appear, but that
              character must be quoted, for example '-\+'.

              Each optarg following an optspec must take one of the following forms:

              :message:action
              ::message:action
                     An argument to the option; message and  action  are  treated  as  for
                     ordinary  arguments.   In  the first form, the argument is mandatory,
                     and in the second form it is optional.

                     This group may be repeated for options which take multiple arguments.
                     In other words, :message1:action1:message2:action2 specifies that the
                     option takes two arguments.

              :*pattern:message:action
              :*pattern::message:action
              :*pattern:::message:action
                     This describes multiple arguments.   Only  the  last  optarg  for  an
                     option  taking  multiple arguments may be given in this form.  If the
                     pattern is empty (i.e., :*:), all the remaining words on the line are
                     to  be completed as described by the action; otherwise, all the words
                     up to and including a word matching the pattern are to  be  completed
                     using the action.

                     Multiple  colons  are  treated  as for the '*:...' forms for ordinary
                     arguments:  when the message is preceded by  two  colons,  the  words
                     special  array  and the CURRENT special parameter are modified during
                     the execution or evaluation of the action to refer only to the  words
                     after  the  option.  When preceded by three colons, they are modified
                     to refer only to the words covered by this description.

       Any literal colon in an optname, message, or action must be  preceded  by  a  back-
       slash, '\:'.

       Each  of  the  forms above may be preceded by a list in parentheses of option names
       and argument numbers.  If the given option is on the command line, the options  and
       arguments indicated in parentheses will not be offered.  For example, '(-two -three
       1)-one:...' completes the option '-one'; if this appears on the command  line,  the
       options -two and -three and the first ordinary argument will not be completed after
       it.  '(-foo):...' specifies an ordinary argument completion; -foo will not be  com-
       pleted if that argument is already present.

       Other  items  may  appear in the list of excluded options to indicate various other
       items that should not be applied when the current specification is matched: a  sin-
       gle  star  (*) for the rest arguments (i.e. a specification of the form '*:...'); a
       colon (:) for all normal (non-option-) arguments; and a hyphen (-) for all options.
       For  example,  if '(*)' appears before an option and the option appears on the com-
       mand line, the list of remaining arguments (those shown in the above  table  begin-
       ning with '*:') will not be completed.

       To aid in reuse of specifications, it is possible to precede any of the forms above
       with '!'; then the form will no longer be completed,  although  if  the  option  or
       argument  appears on the command line they will be skipped as normal.  The main use
       for this is when the arguments are given by an  array,  and  _arguments  is  called
       repeatedly   for   more   specific   contexts:   on   the  first  call  '_arguments
       $global_options' is used, and on subsequent calls '_arguments !$^global_options'.

       In each of the forms above the action determines how completions should  be  gener-
       ated.  Except for the '->string' form below, the action will be executed by calling
       the _all_labels function to process all tag labels.  No special handling of tags is
       needed unless a function call introduces a new one.

       The forms for action are as follows.

         (single unquoted space)
              This  is  useful  where  an  argument  is required but it is not possible or
              desirable to generate matches for it.  The message will be displayed but  no
              completions listed.  Note that even in this case the colon at the end of the
              message is needed; it may only be omitted when  neither  a  message  nor  an
              action is given.

       (item1 item2 ...)
              One of a list of possible matches, for example:

                     :foo:(foo bar baz)

       ((item1\:desc1 ...))
              Similar  to  the above, but with descriptions for each possible match.  Note
              the backslash before the colon.  For example,

                     :foo:((a\:bar b\:baz))

              The matches will be listed together with their descriptions if the  descrip-
              tion style is set with the values tag in the context.

       ->string
              In  this  form,  _arguments  processes  the  arguments  and options and then
              returns control to the calling function with parameters set to indicate  the
              state  of  processing;  the calling function then makes its own arrangements
              for generating completions.  For example, functions that implement  a  state
              machine can use this type of action.

              Where  _arguments  encounters  a  '->string',  it will strip all leading and
              trailing whitespace from string and set the array state to the  set  of  all
              stringss for which an action is to be performed.

              By  default  and in common with all other well behaved completion functions,
              _arguments returns status zero if it was able to add  matches  and  non-zero
              otherwise.  However,  if  the  -R  option  is given, _arguments will instead
              return a status of 300 to indicate that $state is to be handled.

              In addition to $state, _arguments also sets the global parameters 'context',
              'line'  and  'opt_args'  as  described below, and does not reset any changes
              made to the special parameters such as PREFIX and  words.   This  gives  the
              calling  function  the  choice  of resetting these parameters or propagating
              changes in them.

              A function  calling  _arguments  with  at  least  one  action  containing  a
              '->string' must therefore declare appropriate local parameters:

                     local context state line
                     typeset -A opt_args

              to prevent _arguments from altering the global environment.

       {eval-string}
              A  string  in braces is evaluated as shell code to generate matches.  If the
              eval-string itself does not begin with an opening parenthesis or brace it is
              split into separate words before execution.

       = action
              If  the action starts with '= ' (an equals sign followed by a space), _argu-
              ments will insert the contents of the argument field of the current  context
              as  the new first element in the words special array and increment the value
              of the CURRENT special parameter.  This has the effect of inserting a  dummy
              word  onto the completion command line while not changing the point at which
              completion is taking place.

              This is most useful with one of the specifiers that restrict  the  words  on
              the command line on which the action is to operate (the two- and three-colon
              forms above).  One particular use is when an action itself causes _arguments
              on a restricted range; it is necessary to use this trick to insert an appro-
              priate command name into the range for the second call to _arguments  to  be
              able to parse the line.

        word...
       word...
              This  covers  all forms other than those above.  If the action starts with a
              space, the remaining list of words will be invoked unchanged.

              Otherwise it will be invoked with some extra strings placed after the  first
              word;  these  are to be passed down as options to the compadd builtin.  They
              ensure that the state specified by _arguments, in  particular  the  descrip-
              tions  of  options and arguments, is correctly passed to the completion com-
              mand.  These additional arguments are taken from the array parameter 'expl';
              this will be set up before executing the action and hence may be referred to
              inside it, typically in an expansion of the form '$expl[@]' which  preserves
              empty elements of the array.

       During  the  performance  of the action the array 'line' will be set to the command
       name and normal arguments from the command line, i.e. the words  from  the  command
       line excluding all options and their arguments.  Options are stored in the associa-
       tive array 'opt_args' with option names as keys and their arguments as the  values.
       For  options  that have more than one argument these are given as one string, sepa-
       rated by colons.  All colons in the original  arguments  are  preceded  with  back-
       slashes.

       The parameter 'context' is set when returning to the calling function to perform an
       action of the form '->string'.  It is set to an array of elements corresponding  to
       the  elements of $state.  Each element is a suitable name for the argument field of
       the context: either a string of the form 'option-opt-n' for the  n'th  argument  of
       the  option  -opt, or a string of the form 'argument-n' for the n'th argument.  For
       'rest' arguments, that is those in the list at the end not handled by  position,  n
       is  the string 'rest'.  For example, when completing the argument of the -o option,
       the name is 'option-o-1', while for the second normal (non-option-) argument it  is
       'argument-2'.

       Furthermore, during the evaluation of the action the context name in the curcontext
       parameter is altered to append the same string that is stored in the context param-
       eter.

       It is possible to specify multiple sets of options and arguments with the sets sep-
       arated by single hyphens.  The specifications before the first hyphen (if any)  are
       shared  by  all  the  remaining sets.  The first word in every other set provides a
       name for the set which may appear in  exclusion  lists  in  specifications,  either
       alone  or  before one of the possible values described above.  In the second case a
       '-' should appear between this name and the remainder.

       For example:

              _arguments \
                  -a \
                - set1 \
                  -c \
                - set2 \
                  -d \
                  ':arg:(x2 y2)'

       This defines two sets.  When the command line contains the option  '-c',  the  '-d'
       option  and the argument will not be considered possible completions.  When it con-
       tains '-d' or an argument, the option '-c' will not be considered.  However,  after
       '-a' both sets will still be considered valid.

       If  the  name  given for one of the mutually exclusive sets is of the form '(name)'
       then only one value from each set will ever be completed; more formally, all speci-
       fications are mutually exclusive to all other specifications in the same set.  This
       is useful for defining multiple sets of options which are mutually exclusive and in
       which the options are aliases for each other.  For example:

              _arguments \
                  -a -b \
                - '(compress)' \
                  {-c,--compress}'[compress]' \
                - '(uncompress)' \
                  {-d,--decompress}'[decompress]'

       As  the  completion code has to parse the command line separately for each set this
       form of argument is slow and should only be used when necessary.  A useful alterna-
       tive  is  often  an  option specification with rest-arguments (as in '-foo:*:...');
       here the option -foo swallows up all remaining arguments as described by the optarg
       definitions.

       The  options  -S  and  -A are available to simplify the specifications for commands
       with standard option parsing.  With -S, no option will be completed  after  a  '--'
       appearing on its own on the line; this argument will otherwise be ignored; hence in
       the line

              foobar -a -- -b

       the '-a' is considered an option but the '-b' is considered an argument, while  the
       '--' is considered to be neither.

       With  -A,  no  options will be completed after the first non-option argument on the
       line.  The -A must be followed by a pattern matching all strings which are  not  to
       be  taken  as  arguments.   For example, to make _arguments stop completing options
       after the first normal argument, but ignoring all strings starting  with  a  hyphen
       even if they are not described by one of the optspecs, the form is '-A "-*"'.

       The  option  '-O name' specifies the name of an array whose elements will be passed
       as arguments to functions called to execute actions.  For example, this can be used
       to pass the same set of options for the compadd builtin to all actions.

       The  option  '-M spec' sets a match specification to use to completion option names
       and values.  It must appear before the first argument specification.   The  default
       is  'r:|[_-]=*  r:|=*':  this allows partial word completion after '_' and '-', for
       example '-f-b' can be completed to '-foo-bar'.

       The option -C tells _arguments to modify the curcontext parameter for an action  of
       the  form '->state'.  This is the standard parameter used to keep track of the cur-
       rent context.  Here it (and not the context array) should  be  made  local  to  the
       calling function to avoid passing back the modified value and should be initialised
       to the current value at the start of the function:

              local curcontext="$curcontext"

       This is useful where it is not possible for multiple states to be valid together.

       The option '--' allows _arguments to work out the names of long options  that  sup-
       port  the '--help' option which is standard in many GNU commands.  The command word
       is called with the argument '--help' and the  output  examined  for  option  names.
       Clearly,  it  can  be dangerous to pass this to commands which may not support this
       option as the behaviour of the command is unspecified.

       In addition to options, '_arguments --' will try to deduce the types  of  arguments
       available  for  options when the form '--opt=val' is valid.  It is also possible to
       provide hints by examining the help text of the command and  adding  specifiers  of
       the  form  'pattern:message:action'; note that normal _arguments specifiers are not
       used.  The pattern is matched against the help  text  for  an  option,  and  if  it
       matches  the  message  and  action  are used as for other argument specifiers.  For
       example:

              _arguments -- '*\*:toggle:(yes no)' \
                            '*=FILE*:file:_files' \
                            '*=DIR*:directory:_files -/' \
                            '*=PATH*:directory:_files -/'

       Here, 'yes' and 'no' will be completed as the argument of options whose description
       ends in a star; file names will be completed for options that contain the substring
       '=FILE' in the description; and directories will be  completed  for  options  whose
       description contains '=DIR' or '=PATH'.  The last three are in fact the default and
       so need not be given explicitly, although it is possible to  override  the  use  of
       these patterns.  A typical help text which uses this feature is:

                -C, --directory=DIR          change to directory DIR

       so  that  the  above  specifications  will  cause directories to be completed after
       '--directory', though not after '-C'.

       Note also that _arguments tries to find out automatically if the  argument  for  an
       option  is optional.  This can be specified explicitly by doubling the colon before
       the message.

       If the pattern ends in '(-)', this will be removed from the pattern and the  action
       will  be  used  only  directly  after  the  '=', not in the next word.  This is the
       behaviour of a normal specification defined with the form '=-'.

       The '_arguments --' can be followed by the option '-i patterns'  to  give  patterns
       for  options  which are not to be completed.  The patterns can be given as the name
       of an array parameter or as a literal list in parentheses.  For example,

              _arguments -- -i \
                  "(--(en|dis)able-FEATURE*)"

       will cause completion to ignore the options '--enable-FEATURE' and  '--disable-FEA-
       TURE' (this example is useful with GNU configure).

       The  '_arguments  --' form can also be followed by the option '-s pair' to describe
       option aliases.  Each pair consists of a pattern and a replacement.   For  example,
       some  configure-scripts  describe  options  only as '--enable-foo', but also accept
       '--disable-foo'.  To allow completion of the second form:

              _arguments -- -s "(#--enable- --disable-)"

       Here is a more general example of the use of _arguments:

              _arguments '-l+:left border:' \
                         '-format:paper size:(letter A4)' \
                         '*-copy:output file:_files::resolution:(300 600)' \
                         ':postscript file:_files -g \*.\(ps\|eps\)' \
                         '*:page number:'

       This describes three options: '-l', '-format', and '-copy'.  The  first  takes  one
       argument described as 'left border' for which no completion will be offered because
       of the empty action.  Its argument may come directly after the '-l' or  it  may  be
       given as the next word on the line.

       The '-format' option takes one argument in the next word, described as 'paper size'
       for which only the strings 'letter' and 'A4' will be completed.

       The '-copy' option may appear more than once on the  command  line  and  takes  two
       arguments.  The first is mandatory and will be completed as a filename.  The second
       is optional (because of the second colon before the description  'resolution')  and
       will be completed from the strings '300' and '600'.

       The  last  two  descriptions  say what should be completed as arguments.  The first
       describes the first argument as a 'postscript file' and makes files ending in  'ps'
       or 'eps' be completed.  The last description gives all other arguments the descrip-
       tion 'page numbers' but does not offer completions.

       _cache_invalid cache_identifier
              This function returns status zero if the completions cache corresponding  to
              the  given cache identifier needs rebuilding.  It determines this by looking
              up the cache-policy style for the current context.  This  should  provide  a
              function  name which is run with the full path to the relevant cache file as
              the only argument.

              Example:

                     _example_caching_policy () {
                         # rebuild if cache is more than a week old
                         local -a oldp
                         oldp=( "$1"(Nmw+1) )
                         (( $#oldp ))
                     }

       _call_function return name [ args ... ]
              If a function name exists, it is called with the arguments args.  The return
              argument  gives  the name of a parameter in which the return status from the
              function name should be stored; if return is empty or a single hyphen it  is
              ignored.

              The  return  status  of  _call_function  itself is zero if the function name
              exists and was called and non-zero otherwise.

       _call_program tag string ...
              This function provides a mechanism for the user to override the  use  of  an
              external  command.  It looks up the command style with the supplied tag.  If
              the style is set, its value is used as the command to execute.  The  strings
              from  the  call to _call_program, or from the style if set, are concatenated
              with spaces between them and the resulting string is evaluated.  The  return
              status is the return status of the command called.

       _combination [ -s pattern ] tag style spec ... field opts ...
              This function is used to complete combinations of values,  for example pairs
              of hostnames and usernames.   The  style  argument  gives  the  style  which
              defines the pairs; it is looked up in a context with the tag specified.

              The  style  name  consists  of field names separated by hyphens, for example
              'users-hosts-ports'.  For each field for a value is already known, a spec of
              the  form 'field=pattern' is given.  For example, if the command line so far
              specifies a user 'pws', the argument 'users=pws' should appear.

              The next argument with no equals sign is taken as the name of the field  for
              which  completions should be generated (presumably not one of the fields for
              which the value is known).

              The matches generated will be taken from the  value  of  the  style.   These
              should  contain  the possible values for the combinations in the appropriate
              order (users, hosts, ports in the example above).  The different fields  the
              values  for  the  different  fields  are  separated  by colons.  This can be
              altered with the option -s to _combination which specifies a pattern.  Typi-
              cally  this  is a character class, as for example '-s "[:@]"' in the case of
              the users-hosts style.    Each 'field=pattern' specification  restricts  the
              completions which apply to elements of the style with appropriately matching
              fields.

              If no style with the given name is defined for the given tag, or if none  of
              the  strings  in  style's  value  match, but a function name of the required
              field preceded by an underscore is defined, that function will be called  to
              generate the matches.  For example, if there is no 'users-hosts-ports' or no
              matching hostname when a host is required, the function '_hosts' will  auto-
              matically be called.

              If  the  same  name is used for more than one field, in both the 'field=pat-
              tern' and the argument that gives the name of the field to be completed, the
              number  of  the  field (starting with one) may be given after the fieldname,
              separated from it by a colon.

              All arguments after the required field name are passed to compadd when  gen-
              erating  matches from the style value, or to the functions for the fields if
              they are called.

       _describe [ -oO | -t tag ] descr name1 [ name2 ] opts ... -- ...
              This function associates completions  with  descriptions.   Multiple  groups
              separated  by  --  can  be  supplied,  potentially with different completion
              options opts.

              The descr is taken as a string to display above the matches  if  the  format
              style for the descriptions tag is set.  This is followed by one or two names
              of arrays followed by options to pass to compadd.  The first array  contains
              the  possible  completions  with  their  descriptions  in  the form 'comple-
              tion:description'.  Any literal colons in completion must be quoted  with  a
              backslash.   If  a  second array is given, it should have the same number of
              elements as the first; in this case the corresponding elements are added  as
              possible completions instead of the completion strings from the first array.
              The completion list will retain  the  descriptions  from  the  first  array.
              Finally, a set of completion options can appear.

              If the option '-o' appears before the first argument, the matches added will
              be treated as names of command options (N.B. not shell  options),  typically
              following  a  '-',  '--' or '+' on the command line.  In this case _describe
              uses the prefix-hidden, prefix-needed and verbose styles to find out if  the
              strings  should  be  added  as completions and if the descriptions should be
              shown.  Without the '-o' option, only the verbose style is  used  to  decide
              how  descriptions  are  shown.   If  '-O'  is  used instead of '-o', command
              options are completed as above  but  _describe  will  not  handle  the  pre-
              fix-needed style.

              With  the  -t option a tag can be specified.  The default is 'values' or, if
              the -o option is given, 'options'.

              If selected by the list-grouped style, strings  with  the  same  description
              will appear together in the list.

              _describe  uses the _all_labels function to generate the matches, so it does
              not need to appear inside a loop over tag labels.

       _description [ -x ] [ -12VJ ] tag name descr [ spec ... ]
              This function is not to be confused with the previous one; it is used  as  a
              helper  function  for creating options to compadd.  It is buried inside many
              of the higher level completion functions and so often does not  need  to  be
              called directly.

              The  styles  listed  below are tested in the current context using the given
              tag.  The resulting options for compadd are put into the  array  named  name
              (this  is  traditionally  'expl', but this convention is not enforced).  The
              description for the corresponding set of matches is passed to  the  function
              in descr.

              The  styles  tested  are:  format,  hidden,  matcher,  ignored-patterns  and
              group-name.  The format style is first tested for the given tag and then for
              the  descriptions  tag  if  no value was found, while the remainder are only
              tested for the tag given as the first argument.   The  function  also  calls
              _setup which tests some more styles.

              The  string  returned  by the format style (if any) will be modified so that
              the sequence '%d' is replaced by the descr given as the third argument with-
              out  any  leading  or  trailing  white  space.  If, after removing the white
              space, the descr is the empty string, the format style will not be used  and
              the  options  put into the name array will not contain an explanation string
              to be displayed above the matches.

              If _description is called with more than  three  arguments,  the  additional
              specs  should  be  of  the  form  'char:str'.   These supply escape sequence
              replacements for the format style:  every  appearance  of  '%char'  will  be
              replaced by string.

              If  the  -x option is given, the description will be passed to compadd using
              the -x option instead of the default -X.  This means  that  the  description
              will be displayed even if there are no corresponding matches.

              The  options  placed in the array name take account of the group-name style,
              so matches are placed in a separate group where necessary.  The  group  nor-
              mally  has its elements sorted (by passing the option -J to compadd), but if
              an option starting with '-V', '-J', '-1', or '-2' is passed to _description,
              that  option  will  be  included in the array.  Hence it is possible for the
              completion group to be unsorted by giving the option '-V', '-1V', or  '-2V'.

              In most cases, the function will be used like this:

                     local expl
                     _description files expl file
                     compadd "$expl[@]" - "$files[@]"

              Note  the  use  of  the parameter expl, the hyphen, and the list of matches.
              Almost all calls to compadd within the completion system use a similar  for-
              mat;  this  ensures  that user-specified styles are correctly passed down to
              the builtins which implement the internals of completion.

       _dispatch context string ...
              This sets the current context to context and looks for completion  functions
              to  handle this context by hunting through the list of command names or spe-
              cial contexts (as described above for compdef) given  as  string  ....   The
              first  completion function to be defined for one of the contexts in the list
              is used to generate matches.  Typically, the last  string  is  -default-  to
              cause the function for default completion to be used as a fallback.

              The function sets the parameter $service to the string being tried, and sets
              the context/command field (the fourth) of the $curcontext parameter  to  the
              context given as the first argument.

       _files The  function  _files calls _path_files with all the arguments it was passed
              except for -g and -/.  The use of these two options depends on  the  setting
              of the  file-patterns style.

              This  function  accepts  the  full  set  of  options allowed by _path_files,
              described below.

       _gnu_generic
              This function is a simple wrapper around the _arguments  function  described
              above.   It  can  be used to determine automatically the long options under-
              stood by commands that produce a list when passed the option  '--help'.   It
              is  intended to be used as a top-level completion function in its own right.
              For example, to enable option completion for the commands foo and bar, use

                     compdef _gnu_generic foo bar

              after the call to compinit.

              The completion system as supplied is conservative in its use of  this  func-
              tion,  since  it  is important to be sure the command understands the option
              '--help'.

       _guard [ options ] pattern descr
              This function is intended to be used in the action  for  the  specifications
              passed  to  _arguments and similar functions.  It returns immediately with a
              non-zero return status if the string to be completed does not match the pat-
              tern.   If  the  pattern  matches, the descr is displayed; the function then
              returns status zero if the word to complete is not  empty,  non-zero  other-
              wise.

              The pattern may be preceded by any of the options understood by compadd that
              are passed down from _description, namely -M, -J, -V, -1, -2, -n, -F and -X.
              All  of  these  options will be ignored.  This fits in conveniently with the
              argument-passing conventions of actions for _arguments.

              As an example, consider a command taking the options -n and -none, where  -n
              must be followed by a numeric value in the same word.  By using:

                     _arguments '-n-: :_guard "[0-9]#" "numeric value"' '-none'

              _arguments  can be made to both display the message 'numeric value' and com-
              plete options after '-n<TAB>'.  If the '-n' is already followed  by  one  or
              more  digits  (the  pattern  passed to _guard) only the message will be dis-
              played; if the '-n' is followed by another character, only options are  com-
              pleted.

       _message [ -r12 ] [ -VJ group ] descr
       _message -e [ tag ] descr
              The  descr is used in the same way as the third argument to the _description
              function, except that the resulting string will always be shown  whether  or
              not matches were generated.  This is useful for displaying a help message in
              places where no completions can be generated.

              The format style is examined with the messages tag to find  a  message;  the
              usual  tag, descriptions, is used only if the style is not set with the for-
              mer.

              If the -r option is given, no style is used; the descr is taken literally as
              the  string  to  display.   This  is most useful when the descr comes from a
              pre-processed argument list which already contains an expanded  description.

              The  -12VJ  options  and the group are passed to compadd and hence determine
              the group the message string is added to.

              The second form gives a description for completions with the tag tag  to  be
              shown even if there are no matches for that tag.  The tag can be omitted and
              if so the tag is taken from the parameter $curtag; this is maintained by the
              completion system and so is usually correct.

       _multi_parts sep array
              The argument sep is a separator character.  The array may be either the name
              of an array parameter or a literal array in the form '(foo bar)',  a  paren-
              thesised  list  of  words separated by whitespace.  The possible completions
              are the strings from the array.  However, each chunk delimited by  sep  will
              be  completed separately.  For example, the _tar function uses '_multi_parts
              / patharray' to complete partial file paths from the given array of complete
              file paths.

              The  -i  option  causes  _multi_parts  to insert a unique match even if that
              requires multiple separators to  be  inserted.   This  is  not  usually  the
              expected  behaviour  with  filenames, but certain other types of completion,
              for example those with a fixed set of possibilities, may be more  suited  to
              this form.

              Like  other  utility  functions, this function accepts the '-V', '-J', '-1',
              '-2', '-n', '-f', '-X', '-M', '-P', '-S', '-r', '-R', and '-q'  options  and
              passes them to the compadd builtin.

       _next_label [ -x ] [ -12VJ ] tag name descr [ options ... ]
              This  function is used to implement the loop over different tag labels for a
              particular tag as described above for the tag-order style.  On each call  it
              checks  to see if there are any more tag labels; if there is it returns sta-
              tus zero, otherwise non-zero.  As this function requires a current tag to be
              set, it must always follow a call to _tags or _requested.

              The -x12VJ options and the first three arguments are passed to the _descrip-
              tion function.  Where appropriate the tag will be replaced by a tag label in
              this call.  Any description given in the tag-order style is preferred to the
              descr passed to _next_label.

              The options given after the descr are set in the parameter  given  by  name,
              and  hence are to be passed to compadd or whatever function is called to add
              the matches.

              Here is a typical use of this  function  for  the  tag  foo.   The  call  to
              _requested  determines  if  tag  foo  is  required  at  all;  the  loop over
              _next_label handles any labels defined for the tag in the tag-order style.

                     local expl ret=1
                     ...
                     if _requested foo; then
                       ...
                       while _next_label foo expl '...'; do
                         compadd "$expl[@]" ... && ret=0
                       done
                       ...
                     fi
                     return ret

       _normal
              This is the standard function called to handle completion outside  any  spe-
              cial -context-.  It is called both to complete the command word and also the
              arguments for a command.  In the second case, _normal looks  for  a  special
              completion for that command, and if there is none it uses the completion for
              the -default- context.

              A second use is to reexamine the command line specified by the $words  array
              and the $CURRENT parameter after those have been modified.  For example, the
              function _precommand, which completes after pre-command specifiers  such  as
              nohup,  removes  the first word from the words array, decrements the CURRENT
              parameter, then calls _normal again.  The effect is that 'nohup cmd ...'  is
              treated in the same way as 'cmd ...'.

              If  the command name matches one of the patterns given by one of the options
              -p or -P to compdef, the corresponding completion  function  is  called  and
              then  the parameter _compskip is checked.  If it is set completion is termi-
              nated at that point even if no matches have been found.  This  is  the  same
              effect as in the -first- context.

       _options
              This  can  be  used  to  complete the names of shell options.  It provides a
              matcher specification that ignores a leading 'no', ignores  underscores  and
              allows  upper-case letters to match their lower-case counterparts (for exam-
              ple, 'glob', 'noglob', 'NO_GLOB' are  all  completed).   Any  arguments  are
              propagated to the compadd builtin.

       _options_set and _options_unset
              These  functions  complete only set or unset options, with the same matching
              specification used in the _options function.

              Note that you need to uncomment a few lines in the  _main_complete  function
              for  these  functions  to  work properly.  The lines in question are used to
              store the option settings in effect before  the  completion  widget  locally
              sets  the options it needs.  Hence these functions are not generally used by
              the completion system.

       _parameters
              This is used to complete the names of shell parameters.

              The option '-g pattern' limits  the  completion  to  parameters  whose  type
              matches  the  pattern.   The  type  of  a  parameter is that shown by 'print
              ${(t)param}', hence judicious use of '*' in pattern is probably necessary.

              All other arguments are passed to the compadd builtin.

       _path_files
              This function is used throughout the completion  system  to  complete  file-
              names.   It  allows  completion  of  partial paths.  For example, the string
              '/u/i/s/sig' may be completed to '/usr/include/sys/signal.h'.

              The options accepted by both _path_files and _files are:

              -f     Complete all filenames.  This is the default.

              -/     Specifies that only directories should be completed.

              -g pattern
                     Specifies that only files matching the pattern should be completed.

              -W paths
                     Specifies path prefixes that are to be prepended to the  string  from
                     the  command  line  to  generate the filenames but that should not be
                     inserted as completions nor  shown  in  completion  listings.   Here,
                     paths  may be the name of an array parameter, a literal list of paths
                     enclosed in parentheses or an absolute pathname.

              -F ignored-files
                     This behaves as for the corresponding option to the compadd  builtin.
                     It  gives  direct control over which filenames should be ignored.  If
                     the option is not present, the ignored-patterns style is used.

              Both _path_files and _files also accept  the  following  options  which  are
              passed  to  compadd:  '-J',  '-V', '-1', '-2', '-n', '-X', '-M', '-P', '-S',
              '-q', '-r', and '-R'.

              Finally, the _path_files function  uses the styles expand,  ambiguous,  spe-
              cial-dirs, list-suffixes and file-sort described above.

       _pick_variant [ -b builtin-label ] [ -c
              command ] [ -r name ]
          label=pattern ... label [ args ... ]
              This  function  is  used  to  resolve situations where a single command name
              requires more than one type of handling, either because it has more than one
              variant or because there is a name clash between two different commands.

              The command to run is taken from the first element of the array words unless
              this is overridden by the option -c.  This command is run and its output  is
              compared  with  a series of patterns.  Arguments to be passed to the command
              can be specified at the end after all the other arguments.  The patterns  to
              try  in  order  are  given  by the arguments label=pattern; if the output of
              'command args ...' contains pattern, then label is selected as the label for
              the command variant.  If none of the patterns match, the final command label
              is selected and status 1 is returned.

              If the '-b builtin-label' is given, the command is tested to see  if  it  is
              provided  as  a  shell  builtin,  possibly  autoloaded;  if  so,  the  label
              builtin-label is selected as the label for the variant.

              If the '-r name' is given, the label picked is stored in the parameter named
              name.

              The results are also cached in the _cmd_variant associative array indexed by
              the name of the command run.

       _regex_arguments name spec ...
              This function generates a completion function name which matches the  speci-
              fications  spec ..., a set of regular expressions as described below.  After
              running _regex_arguments, the function name should be  called  as  a  normal
              completion  function.  The pattern to be matched is given by the contents of
              the words array up to the current cursor position joined together with  null
              characters; no quotation is applied.

              The  arguments  are  grouped as sets of alternatives separated by '|', which
              are tried one after the other until one matches.  Each alternative  consists
              of  a  one  or  more specifications which are tried left to right, with each
              pattern matched being stripped in turn from the command line  being  tested,
              until  all of the group succeeds or until one fails; in the latter case, the
              next alternative is tried.  This structure  can  be  repeated  to  arbitrary
              depth by using parentheses; matching proceeds from inside to outside.

              A special procedure is applied if no test succeeds but the remaining command
              line string contains no null character (implying the remaining word  is  the
              one  for  which  completions are to be generated).  The completion target is
              restricted to the remaining word  and  any  actions  for  the  corresponding
              patterns  are  executed.  In this case, nothing is stripped from the command
              line string.  The order of evaluation of the actions can  be  determined  by
              the  tag-order  style;  the various formats supported by _alternative can be
              used in action.  The descr is used for setting up the array parameter  expl.

              Specification arguments take one of following forms, in which metacharacters
              such as '(', ')', '#' and '|' should be quoted.

              /pattern/ [%lookahead%] [-guard] [:tag:descr:action]
                     This is a single primitive component.  The function tests whether the
                     combined  pattern  '(#b)((#B)pattern)lookahead*'  matches the command
                     line string.  If so, 'guard' is evaluated and its  return  status  is
                     examined  to determine if the test has succeeded.  The pattern string
                     '[]' is guaranteed never to match.  The  lookahead  is  not  stripped
                     from the command line before the next pattern is examined.

                     The  argument  starting with : is used in the same manner as an argu-
                     ment to _alternative.

                     A component is used as follows: pattern is tested to see if the  com-
                     ponent already exists on the command line.  If it does, any following
                     specifications are examined to find something to complete.  If a com-
                     ponent is reached but no such pattern exists yet on the command line,
                     the string containing the action  is  used  to  generate  matches  to
                     insert at that point.

              /pattern/+ [%lookahead%] [-guard] [:tag:descr:action]
                     This  is  similar to '/pattern/ ...' but the left part of the command
                     line string (i.e. the part already matched by previous  patterns)  is
                     also considered part of the completion target.

              /pattern/- [%lookahead%] [-guard] [:tag:descr:action]
                     This is similar to '/pattern/ ...' but the actions of the current and
                     previously matched patterns are ignored even if the  following  'pat-
                     tern' matches the empty string.

              ( spec )
                     Parentheses  may  be used to groups specs; note each parenthesis is a
                     single argument to _regex_arguments.

              spec # This allows any number of repetitions of spec.

              spec spec
                     The two specs are to be matched one  after  the  other  as  described
                     above.

              spec | spec
                     Either of the two specs can be matched.

              The  function  _regex_words  can  be  used  as a helper function to generate
              matches for a set of alternative words possibly with their own arguments  as
              a command line argument.

              Examples:

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                     /$'[^\0]#\0'/ :'compadd aaa'

              This generates a function _tst that completes aaa as its only argument.  The
              tag and description for the action have been omitted for brevity (this works
              but is not recommended in normal use).  The first component matches the com-
              mand word, which is arbitrary; the second matches   any  argument.   As  the
              argument  is also arbitrary, any following component would not depend on aaa
              being present.

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                     /$'aaa\0'/ :'compadd aaa'

              This is a more typical use; it is similar, but any following patterns  would
              only match if aaa was present as the first argument.

                     _regex_arguments _tst /$'[^\0]#\0'/ \( \
                     /$'aaa\0'/ :'compadd aaa' \
                     /$'bbb\0'/ :'compadd bbb' \) \#

              In this example, an indefinite number of command arguments may be completed.
              Odd arguments are completed as aaa and even arguments  as  bbb.   Completion
              fails  unless  the  set  of  aaa and bbb arguments before the current one is
              matched correctly.

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                     \( /$'aaa\0'/ :'compadd aaa' \| \
                     /$'bbb\0'/ :'compadd bbb' \) \#

              This is similar, but either aaa or bbb may be completed  for  any  argument.
              In  this  case  _regex_words could be used to generate a suitable expression
              for the arguments.


       _regex_words tag description spec ...
              This function can be used to generate  arguments  for  the  _regex_arguments
              command which may be inserted at any point where a set of rules is expected.
              The tag and description give a standard tag and  description  pertaining  to
              the current context.  Each spec contains two or three arguments separated by
              a colon: note that there is no leading colon in this case.

              Each spec gives one of a set of words that may be completed at  this  point,
              together  with  arguments.   It is thus roughly equivalent to the _arguments
              function when used in normal (non-regex) completion.

              The part of the spec before the first colon is the  word  to  be  completed.
              This  may contain a *; the entire word, before and after the * is completed,
              but only the text before the * is required for the context to be matched, so
              that further arguments may be completed after the abbreviated form.

              The second part of spec is a description for the word being completed.

              The  optional  third  part of the spec describes how words following the one
              being completed are themselves to be completed.  It  will  be  evaluated  in
              order to avoid problems with quoting.  This means that typically it contains
              a reference to an array containing previously generated regex arguments.

              The option -t term specifies a terminator for the word instead of the  usual
              space.   This  is  handled  as an auto-removable suffix in the manner of the
              option -s sep to _values.

              The result of the processing by _regex_words is placed in the  array  reply,
              which should be made local to the calling function.  If the set of words and
              arguments may be matched repeatedly, a # should be appended to the generated
              array at that point.

              For example:

                     local -a reply
                     _regex_words mydb-commands 'mydb commands' \
                       'add:add an entry to mydb:$mydb_add_cmds' \
                       'show:show entries in mydb'
                     _regex_arguments _mydb "$reply[@]"
                     _mydb "$@"

              This  shows a completion function for a command mydb which takes two command
              arguments, add and show.  show takes no arguments, while the  arguments  for
              add  have already been prepared in an array mydb_add_cmds, quite possibly by
              a previous call to _regex_words.

       _requested [ -x ] [ -12VJ ] tag [ name descr [ command args ... ] ]
              This function is called to decide whether a tag already registered by a call
              to  _tags  (see  below)  has been requested by the user and hence completion
              should be performed for it.  It returns status zero if the tag is  requested
              and  non-zero  otherwise.   The function is typically used as part of a loop
              over different tags as follows:

                     _tags foo bar baz
                     while _tags; do
                       if _requested foo; then
                         ... # perform completion for foo
                       fi
                       ... # test the tags bar and baz in the same way
                       ... # exit loop if matches were generated
                     done

              Note that the test for whether matches were generated is not performed until
              the  end  of the _tags loop.  This is so that the user can set the tag-order
              style to specify a set of tags to be completed at the same time.

              If name and descr are given, _requested calls the _description function with
              these arguments together with the options passed to _requested.

              If  command  is  given,  the _all_labels function will be called immediately
              with the same arguments.  In simple cases this makes it possible to  perform
              the test for the tag and the matching in one go.  For example:

                     local expl ret=1
                     _tags foo bar baz
                     while _tags; do
                       _requested foo expl 'description' \
                           compadd foobar foobaz && ret=0
                       ...
                       (( ret )) || break
                     done

              If  the  command  is not compadd, it must nevertheless be prepared to handle
              the same options.

       _retrieve_cache cache_identifier
              This function retrieves  completion  information  from  the  file  given  by
              cache_identifier,  stored  in  a directory specified by the cache-path style
              which defaults to ~/.zcompcache.  The return status is zero if retrieval was
              successful.   It  will only attempt retrieval if the use-cache style is set,
              so you can call this function without worrying about whether the user wanted
              to use the caching layer.

              See _store_cache below for more details.

       _sep_parts
              This function is passed alternating arrays and separators as arguments.  The
              arrays specify completions for parts of strings to be separated by the sepa-
              rators.  The arrays may be the names of array parameters or a quoted list of
              words in parentheses.  For example, with the array  'hosts=(ftp  news)'  the
              call '_sep_parts '(foo bar)' @ hosts' will complete the string  'f' to 'foo'
              and the string 'b@n' to 'bar@news'.

              This function accepts the compadd options  '-V',  '-J',  '-1',  '-2',  '-n',
              '-X',  '-M', '-P', '-S', '-r', '-R', and '-q' and passes them on to the com-
              padd builtin used to add the matches.

       _setup tag [ group ]
              This function sets up the special parameters used by the  completion  system
              appropriately  for  the tag given as the first argument.  It uses the styles
              list-colors, list-packed, list-rows-first, last-prompt,  accept-exact,  menu
              and force-list.

              The  optional group supplies the name of the group in which the matches will
              be placed.  If it is not given, the tag is used as the group name.

              This function is called automatically from _description  and  hence  is  not
              normally called explicitly.

       _store_cache cache_identifier params ...
              This  function, together with _retrieve_cache and _cache_invalid, implements
              a caching layer which can be used in any completion function.  Data obtained
              by  costly operations are stored in parameters; this function then dumps the
              values of those parameters to a  file.   The  data  can  then  be  retrieved
              quickly  from  that file via _retrieve_cache, even in different instances of
              the shell.

              The cache_identifier specifies the file which the data should be dumped  to.
              The  file  is  stored in a directory specified by the cache-path style which
              defaults to ~/.zcompcache.  The remaining params arguments are  the  parame-
              ters to dump to the file.

              The return status is zero if storage was successful.  The function will only
              attempt storage if the use-cache style is set, so you can call this function
              without worrying about whether the user wanted to use the caching layer.

              The  completion  function  may avoid calling _retrieve_cache when it already
              has the completion data available as parameters.  However, in that  case  it
              should  call  _cache_invalid to check whether the data in the parameters and
              in the cache are still valid.

              See the _perl_modules completion function for a simple example of the  usage
              of the caching layer.

       _tags [ [ -C name ] tags ... ]
              If  called with arguments, these are taken to be the names of tags valid for
              completions in the current context.  These tags are  stored  internally  and
              sorted by using the tag-order style.

              Next,  _tags is called repeatedly without arguments from the same completion
              function.  This successively selects the first, second,  etc.  set  of  tags
              requested  by  the  user.   The return status is zero if at least one of the
              tags is requested and non-zero otherwise.  To test if a particular tag is to
              be tried, the _requested function should be called (see above).

              If '-C name' is given, name is temporarily stored in the argument field (the
              fifth) of the context in the curcontext parameter during the call to  _tags;
              the  field  is  restored  on exit.  This allows _tags to use a more specific
              context without having to change and reset the curcontext  parameter  (which
              has the same effect).

       _values [ -O name ] [ -s sep ] [ -S sep ] [ -wC ] desc spec ...
              This is used to complete arbitrary keywords (values) and their arguments, or
              lists of such combinations.

              If the first argument is the option '-O name', it will be used in  the  same
              way as by the _arguments function.  In other words, the elements of the name
              array will be passed to compadd when executing an action.

              If the first argument (or the first argument after '-O name') is  '-s',  the
              next argument is used as the character that separates multiple values.  This
              character is automatically added after each value in an auto-removable fash-
              ion  (see  below);  all  values completed by '_values -s' appear in the same
              word on the command line,  unlike  completion  using  _arguments.   If  this
              option is not present, only a single value will be completed per word.

              Normally,  _values  will only use the current word to determine which values
              are already present on the command line and hence are not  to  be  completed
              again.  If the -w option is given, other arguments are examined as well.

              The  first non-option argument is used as a string to print as a description
              before listing the values.

              All other arguments describe the possible values and their arguments in  the
              same  format  used for the description of options by the _arguments function
              (see above).  The only differences  are  that  no  minus  or  plus  sign  is
              required  at the beginning, values can have only one argument, and the forms
              of action beginning with an equal sign are not supported.

              The character separating a value from its argument  can  be  set  using  the
              option -S (like -s, followed by the character to use as the separator in the
              next argument).  By default the equals sign will be used  as  the  separator
              between values and arguments.

              Example:

                     _values -s , 'description' \
                             '*foo[bar]' \
                             '(two)*one[number]:first count:' \
                             'two[another number]::second count:(1 2 3)'

              This describes three possible values: 'foo', 'one', and 'two'.  The first is
              described as 'bar', takes no argument and may appear more  than  once.   The
              second  is  described  as 'number', may appear more than once, and takes one
              mandatory argument described as 'first count'; no action is specified, so it
              will  not be completed.  The '(two)' at the beginning says that if the value
              'one' is on the line, the value 'two' will no longer be considered a  possi-
              ble  completion.   Finally,  the last value ('two') is described as 'another
              number' and takes an optional argument described as 'second count' for which
              the completions (to appear after an '=') are '1', '2', and '3'.  The _values
              function will complete lists of these values separated by commas.

              Like _arguments, this function temporarily adds another context name  compo-
              nent  to the arguments element (the fifth) of the current context while exe-
              cuting the action.  Here this name is just the name of the value  for  which
              the argument is completed.

              The  style verbose is used to decide if the descriptions for the values (but
              not those for the arguments) should be printed.

              The associative array val_args is used to report values and their arguments;
              this  works  similarly to the opt_args associative array used by _arguments.
              Hence the function calling  _values  should  declare  the  local  parameters
              state, line, context and val_args:

                     local context state line
                     typeset -A val_args

              when using an action of the form '->string'.  With this function the context
              parameter will be set to the name of the value whose argument is to be  com-
              pleted.

              Note  also  that  _values  normally adds the character used as the separator
              between values as an auto-removable suffix (similar to a '/' after a  direc-
              tory).  However, this is not possible for a '->string' action as the matches
              for the argument are generated by the calling function.  To  get  the  usual
              behaviour,  the  the calling function can add the separator x as a suffix by
              passing the options '-qS x' either directly or indirectly to compadd.

              The option -C is treated in the same way as it is by  _arguments.   In  that
              case  the  parameter  curcontext should be made local instead of context (as
              described above).

       _wanted [ -x ] [ -C name ]  [ -12VJ ] tag name descr command args ...
              In many contexts,  completion  can  only  generate  one  particular  set  of
              matches, usually corresponding to a single tag.  However, it is still neces-
              sary to decide whether the user requires matches of this type.   This  func-
              tion is useful in such a case.

              The arguments to _wanted are the same as those to _requested, i.e. arguments
              to be passed to _description.  However, in this  case  the  command  is  not
              optional;  all the processing of tags, including the loop over both tags and
              tag labels and the generation of matches, is carried  out  automatically  by
              _wanted.

              Hence  to  offer  only one tag and immediately add the corresponding matches
              with the given description:

                     local expl
                     _wanted tag expl 'description' \
                         compadd matches...

              Note that, as for _requested, the command must be able to accept options  to
              be passed down to compadd.

              Like _tags this function supports the -C option to give a different name for
              the argument context field.  The -x option  has  the  same  meaning  as  for
              _description.


COMPLETION DIRECTORIES
       In  the  source  distribution, the files are contained in various subdirectories of
       the Completion directory.  They may have been installed in the same  structure,  or
       into  one  single  function directory.  The following is a description of the files
       found in the original directory structure.  If you wish to alter an installed file,
       you will need to copy it to some directory which appears earlier in your fpath than
       the standard directory where it appears.

       Base   The core functions and special completion  widgets  automatically  bound  to
              keys.   You will certainly need most of these, though will probably not need
              to alter them.  Many of these are documented above.

       Zsh    Functions for completing arguments of shell  builtin  commands  and  utility
              functions  for this.  Some of these are also used by functions from the Unix
              directory.

       Unix   Functions for completing arguments of external commands and suites  of  com-
              mands.  They may need modifying for your system, although in many cases some
              attempt is made to decide which version of a command is present.  For  exam-
              ple,  completion  for  the mount command tries to determine the system it is
              running on, while completion for many other utilities try to decide  whether
              the  GNU  version  of  the  command  is in use, and hence whether the --help
              option is supported.

       X, AIX, BSD, ...
              Completion and utility function for commands available only on some systems.
              These  are  not arranged hierarchically, so, for example, both the Linux and
              Debian directories, as well as the X directory, may be useful on  your  sys-
              tem.



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