More VERSION tuning: to avoid unnecessary Perl upgrades

[p5sagit/p5-mst-13.2.git] / lib / utf8.pm

diff --git a/lib/utf8.pm b/lib/utf8.pm
index 17ec37b..0885e67 100644 (file)
--- a/lib/utf8.pm
+++ b/lib/utf8.pm
@@ -1,7 +1,10 @@
 package utf8;
 
+
 $utf8::hint_bits = 0x00800000;
 
+our $VERSION = '1.00';
+
 sub import {
     $^H |= $utf8::hint_bits;
     $enc{caller()} = $_[1] if $_[1];
@@ -13,7 +16,8 @@ sub unimport {
 
 sub AUTOLOAD {
     require "utf8_heavy.pl";
-    goto &$AUTOLOAD;
+    goto &$AUTOLOAD if defined &$AUTOLOAD;
+    Carp::croak("Undefined subroutine $AUTOLOAD called");
 }
 
 1;
@@ -21,7 +25,7 @@ __END__
 
 =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
 
@@ -34,9 +38,9 @@ WARNING: The implementation of Unicode support in Perl is incomplete.
 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
@@ -44,32 +48,63 @@ in future we would like to standardize on the UTF-8 encoding for
 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.
+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:
 
-=over
+=over 4
 
 =item *
 
 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 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
     }
 
+=back
+
+=head2 Utility functions
+
+The following functions are defined in the C<utf8::> package by the perl core.
+
+=over 4
+
+=item * $num_octets = utf8::upgrade($string);
+
+Converts internal representation of string to the perls internal UTF-X form.
+Returns the number of octets necessary to represent the string as UTF-X.
+
+=item * utf8::downgrade($string[, CHECK])
+
+Converts internal representation of string to be un-encoded bytes.
+
+=item * utf8::encode($string)
+
+Converts (in-place) I<$string> from logical characters to octet sequence
+representing it in perl's UTF-X encoding.
+
+=item * $flag = utf8::decode($string)
+
+Attempts to convert I<$string> in-place from perl's UTF-X encoding into logical characters.
+
+=back
+
 =head1 SEE ALSO
 
 L<perlunicode>, L<bytes>