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1 | package open; |
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2 | use Carp; |
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3 | $open::hint_bits = 0x20000; |
4 | |
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5 | our $VERSION = '1.01'; |
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6 | |
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7 | my $locale_encoding; |
8 | |
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9 | sub in_locale { $^H & ($locale::hint_bits || 0)} |
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10 | |
11 | sub _get_locale_encoding { |
12 | unless (defined $locale_encoding) { |
276c9210 |
13 | # I18N::Langinfo isn't available everywhere |
9615f2ee |
14 | eval { |
15 | require I18N::Langinfo; |
16 | I18N::Langinfo->import(qw(langinfo CODESET)); |
ba6ce41c |
17 | $locale_encoding = langinfo(CODESET()); |
9615f2ee |
18 | }; |
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19 | my $country_language; |
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20 | |
21 | no warnings 'uninitialized'; |
22 | |
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23 | if (not $locale_encoding && in_locale()) { |
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24 | if ($ENV{LC_ALL} =~ /^([^.]+)\.([^.]+)$/) { |
25 | ($country_language, $locale_encoding) = ($1, $2); |
26 | } elsif ($ENV{LANG} =~ /^([^.]+)\.([^.]+)$/) { |
27 | ($country_language, $locale_encoding) = ($1, $2); |
58d53262 |
28 | } |
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29 | } elsif (not $locale_encoding) { |
30 | if ($ENV{LC_ALL} =~ /\butf-?8\b/i || |
31 | $ENV{LANG} =~ /\butf-?8\b/i) { |
32 | $locale_encoding = 'utf8'; |
33 | } |
34 | # Could do more heuristics based on the country and language |
58d53262 |
35 | # parts of LC_ALL and LANG (the parts before the dot (if any)), |
36 | # since we have Locale::Country and Locale::Language available. |
37 | # TODO: get a database of Language -> Encoding mappings |
421e5dc3 |
38 | # (the Estonian database at http://www.eki.ee/letter/ |
39 | # would be excellent!) --jhi |
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40 | } |
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41 | if (defined $locale_encoding && |
42 | $locale_encoding eq 'euc' && |
43 | defined $country_language) { |
56fb2e42 |
44 | if ($country_language =~ /^ja_JP|japan(?:ese)?$/i) { |
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45 | $locale_encoding = 'euc-jp'; |
5a192dee |
46 | } elsif ($country_language =~ /^ko_KR|korean?$/i) { |
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47 | $locale_encoding = 'euc-kr'; |
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48 | } elsif ($country_language =~ /^zh_CN|chin(?:a|ese)?$/i) { |
49 | $locale_encoding = 'euc-cn'; |
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50 | } elsif ($country_language =~ /^zh_TW|taiwan(?:ese)?$/i) { |
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51 | $locale_encoding = 'euc-tw'; |
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52 | } |
53 | croak "Locale encoding 'euc' too ambiguous" |
54 | if $locale_encoding eq 'euc'; |
55 | } |
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56 | } |
57 | } |
58 | |
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59 | sub import { |
dfebf958 |
60 | my ($class,@args) = @_; |
61 | croak("`use open' needs explicit list of disciplines") unless @args; |
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62 | my $std; |
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63 | $^H |= $open::hint_bits; |
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64 | my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1); |
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65 | while (@args) { |
66 | my $type = shift(@args); |
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67 | my $dscp; |
68 | if ($type =~ /^:?(utf8|locale|encoding\(.+\))$/) { |
69 | $type = 'IO'; |
70 | $dscp = ":$1"; |
b178108d |
71 | } elsif ($type eq ':std') { |
72 | $std = 1; |
73 | next; |
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74 | } else { |
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75 | $dscp = shift(@args) || ''; |
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76 | } |
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77 | my @val; |
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78 | foreach my $layer (split(/\s+/,$dscp)) { |
dfebf958 |
79 | $layer =~ s/^://; |
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80 | if ($layer eq 'locale') { |
81 | use Encode; |
82 | _get_locale_encoding() |
83 | unless defined $locale_encoding; |
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84 | (carp("Cannot figure out an encoding to use"), last) |
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85 | unless defined $locale_encoding; |
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86 | if ($locale_encoding =~ /^utf-?8$/i) { |
87 | $layer = "utf8"; |
88 | } else { |
738b23dc |
89 | $layer = "encoding($locale_encoding)"; |
11fc5dc3 |
90 | } |
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91 | $std = 1; |
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92 | } else { |
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93 | my $target = $layer; # the layer name itself |
94 | $target =~ s/^(\w+)\(.+\)$/$1/; # strip parameters |
95 | |
96 | unless(PerlIO::Layer::->find($target)) { |
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97 | carp("Unknown discipline layer '$layer'"); |
98 | } |
ac27b0f5 |
99 | } |
100 | push(@val,":$layer"); |
101 | if ($layer =~ /^(crlf|raw)$/) { |
102 | $^H{"open_$type"} = $layer; |
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103 | } |
ac27b0f5 |
104 | } |
105 | if ($type eq 'IN') { |
106 | $in = join(' ',@val); |
107 | } |
108 | elsif ($type eq 'OUT') { |
109 | $out = join(' ',@val); |
16fe6d59 |
110 | } |
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111 | elsif ($type eq 'IO') { |
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112 | $in = $out = join(' ',@val); |
113 | } |
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114 | else { |
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115 | croak "Unknown discipline class '$type'"; |
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116 | } |
117 | } |
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118 | ${^OPEN} = join("\0",$in,$out) if $in or $out; |
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119 | if ($std) { |
120 | if ($in) { |
121 | if ($in =~ /:utf8\b/) { |
122 | binmode(STDIN, ":utf8"); |
123 | } elsif ($in =~ /(\w+\(.+\))/) { |
124 | binmode(STDIN, ":$1"); |
125 | } |
126 | } |
127 | if ($out) { |
128 | if ($out =~ /:utf8\b/) { |
129 | binmode(STDOUT, ":utf8"); |
130 | binmode(STDERR, ":utf8"); |
131 | } elsif ($out =~ /(\w+\(.+\))/) { |
132 | binmode(STDOUT, ":$1"); |
133 | binmode(STDERR, ":$1"); |
134 | } |
135 | } |
136 | } |
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137 | } |
138 | |
139 | 1; |
140 | __END__ |
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141 | |
142 | =head1 NAME |
143 | |
144 | open - perl pragma to set default disciplines for input and output |
145 | |
146 | =head1 SYNOPSIS |
147 | |
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148 | use open IN => ":crlf", OUT => ":raw"; |
149 | use open OUT => ':utf8'; |
150 | use open IO => ":encoding(iso-8859-7)"; |
151 | |
152 | use open IO => ':locale'; |
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153 | |
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154 | use open ':utf8'; |
155 | use open ':locale'; |
156 | use open ':encoding(iso-8859-7)'; |
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157 | |
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158 | use open ':std'; |
159 | |
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160 | =head1 DESCRIPTION |
161 | |
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162 | Full-fledged support for I/O disciplines is now implemented provided |
163 | Perl is configured to use PerlIO as its IO system (which is now the |
164 | default). |
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165 | |
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166 | The C<open> pragma serves as one of the interfaces to declare default |
167 | "layers" (aka disciplines) for all I/O. |
168 | |
169 | The C<open> pragma is used to declare one or more default layers for |
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170 | I/O operations. Any open(), readpipe() (aka qx//) and similar |
171 | operators found within the lexical scope of this pragma will use the |
172 | declared defaults. |
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173 | |
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174 | With the C<IN> subpragma you can declare the default layers |
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175 | of input streams, and with the C<OUT> subpragma you can declare |
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176 | the default layers of output streams. With the C<IO> subpragma |
177 | you can control both input and output streams simultaneously. |
178 | |
179 | If you have a legacy encoding, you can use the C<:encoding(...)> tag. |
180 | |
181 | if you want to set your encoding disciplines based on your |
182 | locale environment variables, you can use the C<:locale> tag. |
183 | For example: |
184 | |
185 | $ENV{LANG} = 'ru_RU.KOI8-R'; |
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186 | # the :locale will probe the locale environment variables like LANG |
187 | use open OUT => ':locale'; |
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188 | open(O, ">koi8"); |
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189 | print O chr(0x430); # Unicode CYRILLIC SMALL LETTER A = KOI8-R 0xc1 |
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190 | close O; |
191 | open(I, "<koi8"); |
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192 | printf "%#x\n", ord(<I>), "\n"; # this should print 0xc1 |
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193 | close I; |
194 | |
195 | These are equivalent |
196 | |
197 | use open ':utf8'; |
198 | use open IO => ':utf8'; |
199 | |
200 | as are these |
201 | |
202 | use open ':locale'; |
203 | use open IO => ':locale'; |
204 | |
205 | and these |
206 | |
207 | use open ':encoding(iso-8859-7)'; |
208 | use open IO => ':encoding(iso-8859-7)'; |
209 | |
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210 | When open() is given an explicit list of layers they are appended to |
211 | the list declared using this pragma. |
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212 | |
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213 | The C<:std> subpragma on its own has no effect, but if combined with |
214 | the C<:utf8> or C<:encoding> subpragmas, it converts the standard |
215 | filehandles (STDIN, STDOUT, STDERR) to comply with encoding selected |
216 | for input/output handles. For example, if both input and out are |
217 | chosen to be C<:utf8>, a C<:std> will mean that STDIN, STDOUT, and |
218 | STDERR are also in C<:utf8>. On the other hand, if only output is |
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219 | chosen to be in C<< :encoding(koi8r) >>, a C<:std> will cause only the |
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220 | STDOUT and STDERR to be in C<koi8r>. The C<:locale> subpragma |
221 | implicitly turns on C<:std>. |
222 | |
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223 | The logic of C<:locale> is as follows: |
224 | |
225 | =over 4 |
226 | |
227 | =item 1. |
228 | |
229 | If the platform supports the langinfo(CODESET) interface, the codeset |
230 | returned is used as the default encoding for the open pragma. |
231 | |
232 | =item 2. |
233 | |
234 | If 1. didn't work but we are under the locale pragma, the environment |
235 | variables LC_ALL and LANG (in that order) are matched for encodings |
236 | (the part after C<.>, if any), and if any found, that is used |
237 | as the default encoding for the open pragma. |
238 | |
239 | =item 3. |
240 | |
241 | If 1. and 2. didn't work, the environment variables LC_ALL and LANG |
242 | (in that order) are matched for anything looking like UTF-8, and if |
243 | any found, C<:utf8> is used as the default encoding for the open |
244 | pragma. |
245 | |
246 | =back |
247 | |
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248 | If your locale environment variables (LANGUAGE, LC_ALL, LC_CTYPE, LANG) |
249 | contain the strings 'UTF-8' or 'UTF8' (case-insensitive matching), |
250 | the default encoding of your STDIN, STDOUT, and STDERR, and of |
251 | B<any subsequent file open>, is UTF-8. |
252 | |
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253 | Directory handles may also support disciplines in future. |
254 | |
255 | =head1 NONPERLIO FUNCTIONALITY |
256 | |
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257 | If Perl is not built to use PerlIO as its IO system then only the two |
258 | pseudo-disciplines ":raw" and ":crlf" are available. |
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259 | |
260 | The ":raw" discipline corresponds to "binary mode" and the ":crlf" |
261 | discipline corresponds to "text mode" on platforms that distinguish |
262 | between the two modes when opening files (which is many DOS-like |
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263 | platforms, including Windows). These two disciplines are no-ops on |
264 | platforms where binmode() is a no-op, but perform their functions |
265 | everywhere if PerlIO is enabled. |
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266 | |
267 | =head1 IMPLEMENTATION DETAILS |
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268 | |
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269 | There is a class method in C<PerlIO::Layer> C<find> which is |
270 | implemented as XS code. It is called by C<import> to validate the |
271 | layers: |
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272 | |
273 | PerlIO::Layer::->find("perlio") |
274 | |
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275 | The return value (if defined) is a Perl object, of class |
276 | C<PerlIO::Layer> which is created by the C code in F<perlio.c>. As |
277 | yet there is nothing useful you can do with the object at the perl |
278 | level. |
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279 | |
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280 | =head1 SEE ALSO |
281 | |
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282 | L<perlfunc/"binmode">, L<perlfunc/"open">, L<perlunicode>, L<PerlIO>, |
283 | L<encoding> |
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284 | |
285 | =cut |