- NAME
- encoding — Manipulate encodings
- SYNOPSIS
- INTRODUCTION
- DESCRIPTION
- encoding convertfrom ?encoding? data
- encoding convertto ?encoding? string
- encoding dirs ?directoryList?
- encoding names
- encoding system ?encoding?
- EXAMPLE
- SEE ALSO
- KEYWORDS
encoding — Manipulate encodings
encoding option ?arg arg ...?
Strings in Tcl are logically a sequence of 16-bit Unicode characters.
These strings are represented in memory as a sequence of bytes that
may be in one of several encodings: modified UTF-8 (which uses 1 to 3
bytes per character), 16-bit
“Unicode”
(which uses 2 bytes per character, with an endianness that is
dependent on the host architecture), and binary (which uses a single
byte per character but only handles a restricted range of characters).
Tcl does not guarantee to always use the same encoding for the same
string.
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.
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 single 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 (indeed, the resulting string is a binary string as far as
Tcl is concerned, at least initially). 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.
The encodings
“utf-8”
and
“iso8859-1”
are guaranteed to be present in the list.
- 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.
The following example converts a byte sequence in Japanese euc-jp encoding to a TCL string:
set s [encoding convertfrom euc-jp "\xA4\xCF"]
The result is the unicode codepoint:
“\u306F”,
which is the Hiragana letter HA.
Tcl_GetEncoding
encoding, unicode
Copyright © 1998 Scriptics Corporation.