1Locale::Po4a::TransTractor(3pm)   Po4a Tools   Locale::Po4a::TransTractor(3pm)
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3
4

NAME

6       Locale::Po4a::TransTractor - generic trans(lator ex)tractor.
7

DESCRIPTION

9       The po4a (PO for anything) project goal is to ease translations (and
10       more interestingly, the maintenance of translations) using gettext
11       tools on areas where they were not expected like documentation.
12
13       This class is the ancestor of every po4a parser used to parse a
14       document, to search translatable strings, to extract them to a PO file
15       and to replace them by their translation in the output document.
16
17       More formally, it takes the following arguments as input:
18
19       - a document to translate;
20
21       - a PO file containing the translations to use.
22
23       As output, it produces:
24
25       - another PO file, resulting of the extraction of translatable strings
26         from the input document;
27
28       - a translated document, with the same structure than the one in input,
29         but with all translatable strings replaced with the translations
30         found in the PO file provided in input.
31
32       Here is a graphical representation of this:
33
34          Input document --\                             /---> Output document
35                            \                           /       (translated)
36                             +-> parse() function -----+
37                            /                           \
38          Input PO --------/                             \---> Output PO
39                                                                (extracted)
40

FUNCTIONS YOUR PARSER SHOULD OVERRIDE

42       parse()
43           This is where all the work takes place: the parsing of input
44           documents, the generation of output, and the extraction of the
45           translatable strings. This is pretty simple using the provided
46           functions presented in the section INTERNAL FUNCTIONS below. See
47           also the SYNOPSIS, which presents an example.
48
49           This function is called by the process() function below, but if you
50           choose to use the new() function, and to add content manually to
51           your document, you will have to call this function yourself.
52
53       docheader()
54           This function returns the header we should add to the produced
55           document, quoted properly to be a comment in the target language.
56           See the section Educating developers about translations, from
57           po4a(7), for what it is good for.
58

SYNOPSIS

60       The following example parses a list of paragraphs beginning with "<p>".
61       For the sake of simplicity, we assume that the document is well
62       formatted, i.e. that '<p>' tags are the only tags present, and that
63       this tag is at the very beginning of each paragraph.
64
65        sub parse {
66          my $self = shift;
67
68          PARAGRAPH: while (1) {
69              my ($paragraph,$pararef)=("","");
70              my $first=1;
71              my ($line,$lref)=$self->shiftline();
72              while (defined($line)) {
73                  if ($line =~ m/<p>/ && !$first--; ) {
74                      # Not the first time we see <p>.
75                      # Reput the current line in input,
76                      #  and put the built paragraph to output
77                      $self->unshiftline($line,$lref);
78
79                      # Now that the document is formed, translate it:
80                      #   - Remove the leading tag
81                      $paragraph =~ s/^<p>//s;
82
83                      #   - push to output the leading tag (untranslated) and the
84                      #     rest of the paragraph (translated)
85                      $self->pushline(  "<p>"
86                                      . $document->translate($paragraph,$pararef)
87                                      );
88
89                      next PARAGRAPH;
90                  } else {
91                      # Append to the paragraph
92                      $paragraph .= $line;
93                      $pararef = $lref unless(length($pararef));
94                  }
95
96                  # Reinit the loop
97                  ($line,$lref)=$self->shiftline();
98              }
99              # Did not get a defined line? End of input file.
100              return;
101          }
102        }
103
104       Once you've implemented the parse function, you can use your document
105       class, using the public interface presented in the next section.
106

PUBLIC INTERFACE for scripts using your parser

108   Constructor
109       process(%)
110           This function can do all you need to do with a po4a document in one
111           invocation. Its arguments must be packed as a hash. ACTIONS:
112
113           a. Reads all the PO files specified in po_in_name
114
115           b. Reads all original documents specified in file_in_name
116
117           c. Parses the document
118
119           d. Reads and applies all the addenda specified
120
121           e. Writes the translated document to file_out_name (if given)
122
123           f. Writes the extracted PO file to po_out_name (if given)
124
125           ARGUMENTS, beside the ones accepted by new() (with expected type):
126
127           file_in_name (@)
128               List of filenames where we should read the input document.
129
130           file_in_charset ($)
131               Charset used in the input document (if it isn't specified, it
132               will try to detect it from the input document).
133
134           file_out_name ($)
135               Filename where we should write the output document.
136
137           file_out_charset ($)
138               Charset used in the output document (if it isn't specified, it
139               will use the PO file charset).
140
141           po_in_name (@)
142               List of filenames where we should read the input PO files from,
143               containing the translation which will be used to translate the
144               document.
145
146           po_out_name ($)
147               Filename where we should write the output PO file, containing
148               the strings extracted from the input document.
149
150           addendum (@)
151               List of filenames where we should read the addenda from.
152
153           addendum_charset ($)
154               Charset for the addenda.
155
156       new(%)
157           Create a new po4a document. Accepted options (but be in a hash):
158
159           verbose ($)
160               Sets the verbosity.
161
162           debug ($)
163               Sets the debugging.
164
165   Manipulating document files
166       read($)
167           Add another input document at the end of the existing one. The
168           argument is the filename to read.
169
170           Please note that it does not parse anything. You should use the
171           parse() function when you're done with packing input files into the
172           document.
173
174       write($)
175           Write the translated document to the given filename.
176
177   Manipulating PO files
178       readpo($)
179           Add the content of a file (which name is passed as argument) to the
180           existing input PO. The old content is not discarded.
181
182       writepo($)
183           Write the extracted PO file to the given filename.
184
185       stats()
186           Returns some statistics about the translation done so far. Please
187           note that it's not the same statistics than the one printed by
188           msgfmt --statistic. Here, it's stats about recent usage of the PO
189           file, while msgfmt reports the status of the file. It is a wrapper
190           to the Locale::Po4a::Po::stats_get function applied to the input PO
191           file. Example of use:
192
193               [normal use of the po4a document...]
194
195               ($percent,$hit,$queries) = $document->stats();
196               print "We found translations for $percent\%  ($hit from $queries) of strings.\n";
197
198       is_po_uptodate()
199           Returns ($uptodate, $diagnostic) where $uptodate is whether the
200           input po and the output po match (if not, it means that the input
201           po should be updated) and $diagnostic is a string explaining why
202           the po file is not uptodate, when this happens.
203
204   Manipulating addenda
205       addendum($)
206           Please refer to po4a(7) for more information on what addenda are,
207           and how translators should write them. To apply an addendum to the
208           translated document, simply pass its filename to this function and
209           you are done ;)
210
211           This function returns a non-null integer on error.
212

INTERNAL FUNCTIONS used to write derivated parsers

214   Getting input, providing output
215       Four functions are provided to get input and return output. They are
216       very similar to shift/unshift and push/pop. The first pair is about
217       input, while the second is about output. Mnemonic: in input, you are
218       interested in the first line, what shift gives, and in output you want
219       to add your result at the end, like push does.
220
221       shiftline()
222           This function returns the next line of the doc_in to be parsed and
223           its reference (packed as an array).
224
225       unshiftline($$)
226           Unshifts a line of the input document and its reference.
227
228       pushline($)
229           Push a new line to the doc_out.
230
231       popline()
232           Pop the last pushed line from the doc_out.
233
234   Marking strings as translatable
235       One function is provided to handle the text which should be translated.
236
237       translate($$$)
238           Mandatory arguments:
239
240           - A string to translate
241
242           - The reference of this string (i.e. position in inputfile)
243
244           - The type of this string (i.e. the textual description of its
245             structural role; used in Locale::Po4a::Po::gettextization(); see
246             also po4a(7), section Gettextization: how does it work?)
247
248           This function can also take some extra arguments. They must be
249           organized as a hash. For example:
250
251             $self->translate("string","ref","type",
252                              'wrap' => 1);
253
254           wrap
255               boolean indicating whether we can consider that whitespaces in
256               string are not important. If yes, the function canonizes the
257               string before looking for a translation or extracting it, and
258               wraps the translation.
259
260           wrapcol
261               the column at which we should wrap (default: 76).
262
263           comment
264               an extra comment to add to the entry.
265
266           Actions:
267
268           - Pushes the string, reference and type to po_out.
269
270           - Returns the translation of the string (as found in po_in) so that
271             the parser can build the doc_out.
272
273           - Handles the charsets to recode the strings before sending them to
274             po_out and before returning the translations.
275
276   Misc functions
277       verbose()
278           Returns if the verbose option was passed during the creation of the
279           TransTractor.
280
281       debug()
282           Returns if the debug option was passed during the creation of the
283           TransTractor.
284
285       detected_charset($)
286           This tells TransTractor that a new charset (the first argument) has
287           been detected from the input document. It can usually be read from
288           the document header. Only the first charset will remain, coming
289           either from the process() arguments or detected from the document.
290
291       get_out_charset()
292           This function will return the charset that should be used in the
293           output document (usually useful to substitute the input document's
294           detected charset where it has been found).
295
296           It will use the output charset specified in the command line. If it
297           wasn't specified, it will use the input PO's charset, and if the
298           input PO has the default "CHARSET", it will return the input
299           document's charset, so that no encoding is performed.
300
301       recode_skipped_text($)
302           This function returns the recoded text passed as argument, from the
303           input document's charset to the output document's one. This isn't
304           needed when translating a string (translate() recodes everything
305           itself), but it is when you skip a string from the input document
306           and you want the output document to be consistent with the global
307           encoding.
308

FUTURE DIRECTIONS

310       One shortcoming of the current TransTractor is that it can't handle
311       translated document containing all languages, like debconf templates,
312       or .desktop files.
313
314       To address this problem, the only interface changes needed are:
315
316       - take a hash as po_in_name (a list per language)
317
318       - add an argument to translate to indicate the target language
319
320       - make a pushline_all function, which would make pushline of its
321         content for all languages, using a map-like syntax:
322
323             $self->pushline_all({ "Description[".$langcode."]=".
324                                   $self->translate($line,$ref,$langcode)
325                                 });
326
327       Will see if it's enough ;)
328

AUTHORS

330        Denis Barbier <barbier@linuxfr.org>
331        Martin Quinson (mquinson#debian.org)
332        Jordi Vilalta <jvprat@gmail.com>
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335
336Po4a Tools                        2019-02-02   Locale::Po4a::TransTractor(3pm)
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