=head1 NAME
-utf8 - Perl pragma to enable/disable UTF-8 in source code
+utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code
=head1 SYNOPSIS
See L<perlunicode> for the exact details.
The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the
-program text in the current lexical scope. The C<no utf8> pragma
-tells Perl to switch back to treating the source text as literal
-bytes in the current lexical scope.
+program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based
+platforms). The C<no utf8> pragma tells Perl to switch back to treating
+the source text as literal bytes in the current lexical scope.
This pragma is primarily a compatibility device. Perl versions
earlier than 5.6 allowed arbitrary bytes in source code, whereas
source text. Until UTF-8 becomes the default format for source
text, this pragma should be used to recognize UTF-8 in the source.
When UTF-8 becomes the standard source format, this pragma will
-effectively become a no-op. This pragma already is a no-op on
-EBCDIC platforms (where it is alright to code perl in EBCDIC
-rather than UTF-8).
+effectively become a no-op. For convenience in what follows the
+term UTF-X is used to refer to UTF-8 on ASCII and ISO Latin based
+platforms and UTF-EBCDIC on EBCDIC based platforms.
Enabling the C<utf8> pragma has the following effects:
Bytes in the source text that have their high-bit set will be treated
as being part of a literal UTF-8 character. This includes most literals
such as identifiers, string constants, constant regular expression patterns
-and package names.
+and package names. On EBCDIC platforms, characters in the C1 control group
+and the Latin 1 character set are treated as being part of a literal
+UTF-EBCDIC character.
=item *
-In the absence of inputs marked as UTF-8, regular expressions within the
+In the absence of inputs marked as UTF-X, regular expressions within the
scope of this pragma will default to using character semantics instead
of byte semantics.
@bytes_or_chars = split //, $data; # may split to bytes if data
- # $data isn't UTF-8
+ # $data isn't UTF-X
{
use utf8; # force char semantics
@chars = split //, $data; # splits characters
=item * $flag = utf8::decode($string)
-Attempts to converts I<$string> in-place from perl's UTF-X encoding into logical characters.
+Attempts to convert I<$string> in-place from perl's UTF-X encoding into logical characters.
=back
However, as a compatibility measure, this pragma must be explicitly used
to enable recognition of UTF-8 encoded literals and identifiers in the
-source text.
+source text on ASCII based machines or recognize UTF-EBCDIC encoded literals
+and identifiers on EBCDIC based machines.
=back
Beginning with version 5.6, Perl uses logically wide characters to
represent strings internally. This internal representation of strings
-uses the UTF-8 encoding.
+uses either the UTF-8 or the UTF-EBCDIC encoding.
In future, Perl-level operations can be expected to work with characters
rather than bytes, in general.
byte semantics in a particular lexical scope. See L<bytes>.
The C<utf8> pragma is primarily a compatibility device that enables
-recognition of UTF-8 in literals encountered by the parser. It may also
+recognition of UTF-(8|EBCDIC) in literals encountered by the parser. It may also
be used for enabling some of the more experimental Unicode support features.
Note that this pragma is only required until a future version of Perl
in which character semantics will become the default. This pragma may
no difference, because UTF-8 stores ASCII in single bytes, but for
any character greater than C<chr(127)>, the character may be stored in
a sequence of two or more bytes, all of which have the high bit set.
+For C1 controls or Latin 1 characters on an EBCDIC platform the character
+may be stored in a UTF-EBCDIC multi byte sequence.
But by and large, the user need not worry about this, because Perl
hides it from the user. A character in Perl is logically just a number
ranging from 0 to 2**32 or so. Larger characters encode to longer
larger than 255.
Presuming you use a Unicode editor to edit your program, such characters
-will typically occur directly within the literal strings as UTF-8
+will typically occur directly within the literal strings as UTF-(8|EBCDIC)
characters, but you can also specify a particular character with an
-extension of the C<\x> notation. UTF-8 characters are specified by
+extension of the C<\x> notation. UTF-X characters are specified by
putting the hexadecimal code within curlies after the C<\x>. For instance,
a Unicode smiley face is C<\x{263A}>.
=head1 CAVEATS
As of yet, there is no method for automatically coercing input and
-output to some encoding other than UTF-8. This is planned in the near
-future, however.
+output to some encoding other than UTF-8 or UTF-EBCDIC. This is planned
+in the near future, however.
Whether an arbitrary piece of data will be treated as "characters" or
"bytes" by internal operations cannot be divined at the current time.
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