encoding(n) - phpMan

encoding(n) Tcl Built-In Commands encoding(n)

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NAME
encoding - Manipulate encodings

SYNOPSIS
encoding option ?arg arg ...?
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INTRODUCTION
Strings in Tcl are encoded using 16-bit Unicode characters. Different operating system
interfaces or applications may generate strings in other encodings such as Shift-JIS. The
encoding command helps to bridge the gap between Unicode and these other formats.

DESCRIPTION
Performs one of several encoding related operations, depending on option. The legal
options are:

encoding convertfrom ?encoding? data
Convert data to Unicode from the specified encoding. The characters in data are
treated as binary data where the lower 8-bits of each character is taken as a sin-
gle byte. The resulting sequence of bytes is treated as a string in the specified
encoding. If encoding is not specified, the current system encoding is used.

encoding convertto ?encoding? string
Convert string from Unicode to the specified encoding. The result is a sequence of
bytes that represents the converted string. Each byte is stored in the lower
8-bits of a Unicode character. If encoding is not specified, the current system
encoding is used.

encoding dirs ?directoryList?
Tcl can load encoding data files from the file system that describe additional |
encodings for it to work with. This command sets the search path for *.enc encoding |
data files to the list of directories directoryList. If directoryList is omitted |
then the command returns the current list of directories that make up the search |
path. It is an error for directoryList to not be a valid list. If, when a search |
for an encoding data file is happening, an element in directoryList does not refer |
to a readable, searchable directory, that element is ignored.

encoding names
Returns a list containing the names of all of the encodings that are currently
available.

encoding system ?encoding?
Set the system encoding to encoding. If encoding is omitted then the command
returns the current system encoding. The system encoding is used whenever Tcl
passes strings to system calls.

EXAMPLE
It is common practice to write script files using a text editor that produces output in
the euc-jp encoding, which represents the ASCII characters as singe bytes and Japanese
characters as two bytes. This makes it easy to embed literal strings that correspond to
non-ASCII characters by simply typing the strings in place in the script. However,
because the source command always reads files using the current system encoding, Tcl will
only source such files correctly when the encoding used to write the file is the same.
This tends not to be true in an internationalized setting. For example, if such a file
was sourced in North America (where the ISO8859-1 is normally used), each byte in the file
would be treated as a separate character that maps to the 00 page in Unicode. The result-
ing Tcl strings will not contain the expected Japanese characters. Instead, they will
contain a sequence of Latin-1 characters that correspond to the bytes of the original
string. The encoding command can be used to convert this string to the expected Japanese
Unicode characters. For example,
set s [encoding convertfrom euc-jp "\xA4\xCF"]
would return the Unicode string "\u306F", which is the Hiragana letter HA.