Commit | Line | Data |
---|---|---|
657b208b | 1 | package bytes; |
5bc28da9 | 2 | |
79077e6c | 3 | our $VERSION = '1.03'; |
b75c8c73 | 4 | |
d5448623 GS |
5 | $bytes::hint_bits = 0x00000008; |
6 | ||
5bc28da9 | 7 | sub import { |
d5448623 | 8 | $^H |= $bytes::hint_bits; |
5bc28da9 NIS |
9 | } |
10 | ||
11 | sub unimport { | |
d5448623 | 12 | $^H &= ~$bytes::hint_bits; |
5bc28da9 NIS |
13 | } |
14 | ||
15 | sub AUTOLOAD { | |
657b208b | 16 | require "bytes_heavy.pl"; |
5b5a256a TS |
17 | goto &$AUTOLOAD if defined &$AUTOLOAD; |
18 | require Carp; | |
19 | Carp::croak("Undefined subroutine $AUTOLOAD called"); | |
5bc28da9 NIS |
20 | } |
21 | ||
79077e6c RGS |
22 | sub length (_); |
23 | sub chr (_); | |
24 | sub ord (_); | |
579f6b36 JH |
25 | sub substr ($$;$$); |
26 | sub index ($$;$); | |
27 | sub rindex ($$;$); | |
5bc28da9 NIS |
28 | |
29 | 1; | |
30 | __END__ | |
31 | ||
32 | =head1 NAME | |
33 | ||
657b208b | 34 | bytes - Perl pragma to force byte semantics rather than character semantics |
5bc28da9 NIS |
35 | |
36 | =head1 SYNOPSIS | |
37 | ||
657b208b | 38 | use bytes; |
579f6b36 JH |
39 | ... chr(...); # or bytes::chr |
40 | ... index(...); # or bytes::index | |
41 | ... length(...); # or bytes::length | |
42 | ... ord(...); # or bytes::ord | |
43 | ... rindex(...); # or bytes::rindex | |
44 | ... substr(...); # or bytes::substr | |
657b208b | 45 | no bytes; |
5bc28da9 | 46 | |
579f6b36 | 47 | |
5bc28da9 NIS |
48 | =head1 DESCRIPTION |
49 | ||
657b208b GS |
50 | The C<use bytes> pragma disables character semantics for the rest of the |
51 | lexical scope in which it appears. C<no bytes> can be used to reverse | |
52 | the effect of C<use bytes> within the current lexical scope. | |
393fec97 | 53 | |
5de28535 SC |
54 | Perl normally assumes character semantics in the presence of character |
55 | data (i.e. data that has come from a source that has been marked as | |
56 | being of a particular character encoding). When C<use bytes> is in | |
57 | effect, the encoding is temporarily ignored, and each string is treated | |
58 | as a series of bytes. | |
59 | ||
60 | As an example, when Perl sees C<$x = chr(400)>, it encodes the character | |
c26c758b | 61 | in UTF-8 and stores it in $x. Then it is marked as character data, so, |
5de28535 SC |
62 | for instance, C<length $x> returns C<1>. However, in the scope of the |
63 | C<bytes> pragma, $x is treated as a series of bytes - the bytes that make | |
64 | up the UTF8 encoding - and C<length $x> returns C<2>: | |
65 | ||
66 | $x = chr(400); | |
67 | print "Length is ", length $x, "\n"; # "Length is 1" | |
68 | printf "Contents are %vd\n", $x; # "Contents are 400" | |
69 | { | |
579f6b36 | 70 | use bytes; # or "require bytes; bytes::length()" |
5de28535 SC |
71 | print "Length is ", length $x, "\n"; # "Length is 2" |
72 | printf "Contents are %vd\n", $x; # "Contents are 198.144" | |
73 | } | |
74 | ||
579f6b36 JH |
75 | chr(), ord(), substr(), index() and rindex() behave similarly. |
76 | ||
5de28535 | 77 | For more on the implications and differences between character |
579f6b36 JH |
78 | semantics and byte semantics, see L<perluniintro> and L<perlunicode>. |
79 | ||
80 | =head1 LIMITATIONS | |
81 | ||
82 | bytes::substr() does not work as an lvalue(). | |
393fec97 GS |
83 | |
84 | =head1 SEE ALSO | |
85 | ||
579f6b36 | 86 | L<perluniintro>, L<perlunicode>, L<utf8> |
5bc28da9 NIS |
87 | |
88 | =cut |