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1 | package charnames; |
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2 | |
3 | our $VERSION = '1.00'; |
4 | |
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5 | use bytes (); # for $bytes::hint_bits |
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6 | use warnings(); |
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7 | $charnames::hint_bits = 0x20000; |
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8 | |
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9 | my $txt; |
10 | |
11 | # This is not optimized in any way yet |
12 | sub charnames { |
13 | $name = shift; |
14 | $txt = do "unicode/Name.pl" unless $txt; |
15 | my @off; |
16 | if ($^H{charnames_full} and $txt =~ /\t\t$name$/m) { |
17 | @off = ($-[0], $+[0]); |
18 | } |
19 | unless (@off) { |
20 | if ($^H{charnames_short} and $name =~ /^(.*?):(.*)/s) { |
21 | my ($script, $cname) = ($1,$2); |
22 | my $case = ( $cname =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL"); |
23 | if ($txt =~ m/\t\t\U$script\E (?:$case )?LETTER \U$cname$/m) { |
24 | @off = ($-[0], $+[0]); |
25 | } |
26 | } |
27 | } |
28 | unless (@off) { |
29 | my $case = ( $name =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL"); |
30 | for ( @{$^H{charnames_scripts}} ) { |
31 | (@off = ($-[0], $+[0])), last |
32 | if $txt =~ m/\t\t$_ (?:$case )?LETTER \U$name$/m; |
33 | } |
34 | } |
35 | die "Unknown charname '$name'" unless @off; |
36 | |
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37 | my $ord = hex substr $txt, $off[0] - 4, 4; |
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38 | if ($^H & $bytes::hint_bits) { # "use bytes" in effect? |
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39 | use bytes; |
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40 | return chr $ord if $ord <= 255; |
41 | my $hex = sprintf '%X=0%o', $ord, $ord; |
42 | my $fname = substr $txt, $off[0] + 2, $off[1] - $off[0] - 2; |
43 | die "Character 0x$hex with name '$fname' is above 0xFF"; |
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44 | } |
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45 | return chr $ord; |
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46 | } |
47 | |
48 | sub import { |
49 | shift; |
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50 | die "`use charnames' needs explicit imports list" unless @_; |
51 | $^H |= $charnames::hint_bits; |
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52 | $^H{charnames} = \&charnames ; |
53 | my %h; |
54 | @h{@_} = (1) x @_; |
55 | $^H{charnames_full} = delete $h{':full'}; |
56 | $^H{charnames_short} = delete $h{':short'}; |
57 | $^H{charnames_scripts} = [map uc, keys %h]; |
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58 | if (warnings::enabled('utf8') && @{$^H{charnames_scripts}}) { |
59 | $txt = do "unicode/Name.pl" unless $txt; |
60 | for (@{$^H{charnames_scripts}}) { |
61 | warnings::warn('utf8', "No such script: '$_'") unless |
62 | $txt =~ m/\t\t$_ (?:CAPITAL |SMALL )?LETTER /; |
63 | } |
64 | } |
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65 | } |
66 | |
67 | |
68 | 1; |
69 | __END__ |
70 | |
71 | =head1 NAME |
72 | |
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73 | charnames - define character names for C<\N{named}> string literal escape. |
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74 | |
75 | =head1 SYNOPSIS |
76 | |
77 | use charnames ':full'; |
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78 | print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n"; |
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79 | |
80 | use charnames ':short'; |
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81 | print "\N{greek:Sigma} is an upper-case sigma.\n"; |
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82 | |
83 | use charnames qw(cyrillic greek); |
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84 | print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n"; |
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85 | |
86 | =head1 DESCRIPTION |
87 | |
88 | Pragma C<use charnames> supports arguments C<:full>, C<:short> and |
89 | script names. If C<:full> is present, for expansion of |
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90 | C<\N{CHARNAME}}> string C<CHARNAME> is first looked in the list of |
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91 | standard Unicode names of chars. If C<:short> is present, and |
92 | C<CHARNAME> has the form C<SCRIPT:CNAME>, then C<CNAME> is looked up |
93 | as a letter in script C<SCRIPT>. If pragma C<use charnames> is used |
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94 | with script name arguments, then for C<\N{CHARNAME}}> the name |
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95 | C<CHARNAME> is looked up as a letter in the given scripts (in the |
96 | specified order). |
97 | |
98 | For lookup of C<CHARNAME> inside a given script C<SCRIPTNAME> |
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99 | this pragma looks for the names |
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100 | |
101 | SCRIPTNAME CAPITAL LETTER CHARNAME |
102 | SCRIPTNAME SMALL LETTER CHARNAME |
103 | SCRIPTNAME LETTER CHARNAME |
104 | |
105 | in the table of standard Unicode names. If C<CHARNAME> is lowercase, |
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106 | then the C<CAPITAL> variant is ignored, otherwise the C<SMALL> variant is |
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107 | ignored. |
108 | |
109 | =head1 CUSTOM TRANSLATORS |
110 | |
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111 | The mechanism of translation of C<\N{...}> escapes is general and not |
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112 | hardwired into F<charnames.pm>. A module can install custom |
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113 | translations (inside the scope which C<use>s the module) with the |
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114 | following magic incantation: |
115 | |
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116 | use charnames (); # for $charnames::hint_bits |
117 | sub import { |
118 | shift; |
119 | $^H |= $charnames::hint_bits; |
120 | $^H{charnames} = \&translator; |
121 | } |
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122 | |
123 | Here translator() is a subroutine which takes C<CHARNAME> as an |
124 | argument, and returns text to insert into the string instead of the |
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125 | C<\N{CHARNAME}> escape. Since the text to insert should be different |
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126 | in C<bytes> mode and out of it, the function should check the current |
127 | state of C<bytes>-flag as in: |
128 | |
129 | use bytes (); # for $bytes::hint_bits |
130 | sub translator { |
131 | if ($^H & $bytes::hint_bits) { |
132 | return bytes_translator(@_); |
133 | } |
134 | else { |
135 | return utf8_translator(@_); |
136 | } |
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137 | } |
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138 | |
139 | =head1 BUGS |
140 | |
141 | Since evaluation of the translation function happens in a middle of |
142 | compilation (of a string literal), the translation function should not |
143 | do any C<eval>s or C<require>s. This restriction should be lifted in |
144 | a future version of Perl. |
145 | |
146 | =cut |