1Locale::Maketext(3)   User Contributed Perl Documentation  Locale::Maketext(3)
2
3
4

NAME

6       Locale::Maketext - framework for localization
7

SYNOPSIS

9         package MyProgram;
10         use strict;
11         use MyProgram::L10N;
12          # ...which inherits from Locale::Maketext
13         my $lh = MyProgram::L10N->get_handle() || die "What language?";
14         ...
15         # And then any messages your program emits, like:
16         warn $lh->maketext( "Can't open file [_1]: [_2]\n", $f, $! );
17         ...
18

DESCRIPTION

20       It is a common feature of applications (whether run directly, or via
21       the Web) for them to be "localized" -- i.e., for them to a present an
22       English interface to an English-speaker, a German interface to a
23       German-speaker, and so on for all languages it's programmed with.
24       Locale::Maketext is a framework for software localization; it provides
25       you with the tools for organizing and accessing the bits of text and
26       text-processing code that you need for producing localized
27       applications.
28
29       In order to make sense of Maketext and how all its components fit
30       together, you should probably go read Locale::Maketext::TPJ13, and then
31       read the following documentation.
32
33       You may also want to read over the source for "File::Findgrep" and its
34       constituent modules -- they are a complete (if small) example
35       application that uses Maketext.
36

QUICK OVERVIEW

38       The basic design of Locale::Maketext is object-oriented, and
39       Locale::Maketext is an abstract base class, from which you derive a
40       "project class".  The project class (with a name like
41       "TkBocciBall::Localize", which you then use in your module) is in turn
42       the base class for all the "language classes" for your project (with
43       names "TkBocciBall::Localize::it", "TkBocciBall::Localize::en",
44       "TkBocciBall::Localize::fr", etc.).
45
46       A language class is a class containing a lexicon of phrases as class
47       data, and possibly also some methods that are of use in interpreting
48       phrases in the lexicon, or otherwise dealing with text in that
49       language.
50
51       An object belonging to a language class is called a "language handle";
52       it's typically a flyweight object.
53
54       The normal course of action is to call:
55
56         use TkBocciBall::Localize;  # the localization project class
57         $lh = TkBocciBall::Localize->get_handle();
58          # Depending on the user's locale, etc., this will
59          # make a language handle from among the classes available,
60          # and any defaults that you declare.
61         die "Couldn't make a language handle??" unless $lh;
62
63       From then on, you use the "maketext" function to access entries in
64       whatever lexicon(s) belong to the language handle you got.  So, this:
65
66         print $lh->maketext("You won!"), "\n";
67
68       ...emits the right text for this language.  If the object in $lh
69       belongs to class "TkBocciBall::Localize::fr" and
70       %TkBocciBall::Localize::fr::Lexicon contains "("You won!"  => "Tu as
71       gagné!")", then the above code happily tells the user "Tu as gagné!".
72

METHODS

74       Locale::Maketext offers a variety of methods, which fall into three
75       categories:
76
77       ·   Methods to do with constructing language handles.
78
79       ·   "maketext" and other methods to do with accessing %Lexicon data for
80           a given language handle.
81
82       ·   Methods that you may find it handy to use, from routines of yours
83           that you put in %Lexicon entries.
84
85       These are covered in the following section.
86
87   Construction Methods
88       These are to do with constructing a language handle:
89
90       ·   $lh = YourProjClass->get_handle( ...langtags... ) || die "lg-
91           handle?";
92
93           This tries loading classes based on the language-tags you give
94           (like "("en-US", "sk", "kon", "es-MX", "ja", "i-klingon")", and for
95           the first class that succeeds, returns
96           YourProjClass::language->new().
97
98           If it runs thru the entire given list of language-tags, and finds
99           no classes for those exact terms, it then tries "superordinate"
100           language classes.  So if no "en-US" class (i.e.,
101           YourProjClass::en_us) was found, nor classes for anything else in
102           that list, we then try its superordinate, "en" (i.e.,
103           YourProjClass::en), and so on thru the other language-tags in the
104           given list: "es".  (The other language-tags in our example list:
105           happen to have no superordinates.)
106
107           If none of those language-tags leads to loadable classes, we then
108           try classes derived from YourProjClass->fallback_languages() and
109           then if nothing comes of that, we use classes named by
110           YourProjClass->fallback_language_classes().  Then in the (probably
111           quite unlikely) event that that fails, we just return undef.
112
113       ·   $lh = YourProjClass->get_handle() || die "lg-handle?";
114
115           When "get_handle" is called with an empty parameter list, magic
116           happens:
117
118           If "get_handle" senses that it's running in program that was
119           invoked as a CGI, then it tries to get language-tags out of the
120           environment variable "HTTP_ACCEPT_LANGUAGE", and it pretends that
121           those were the languages passed as parameters to "get_handle".
122
123           Otherwise (i.e., if not a CGI), this tries various OS-specific ways
124           to get the language-tags for the current locale/language, and then
125           pretends that those were the value(s) passed to "get_handle".
126
127           Currently this OS-specific stuff consists of looking in the
128           environment variables "LANG" and "LANGUAGE"; and on MSWin machines
129           (where those variables are typically unused), this also tries using
130           the module Win32::Locale to get a language-tag for whatever
131           language/locale is currently selected in the "Regional Settings"
132           (or "International"?)  Control Panel.  I welcome further
133           suggestions for making this do the Right Thing under other
134           operating systems that support localization.
135
136           If you're using localization in an application that keeps a
137           configuration file, you might consider something like this in your
138           project class:
139
140             sub get_handle_via_config {
141               my $class = $_[0];
142               my $chosen_language = $Config_settings{'language'};
143               my $lh;
144               if($chosen_language) {
145                 $lh = $class->get_handle($chosen_language)
146                  || die "No language handle for \"$chosen_language\""
147                       . " or the like";
148               } else {
149                 # Config file missing, maybe?
150                 $lh = $class->get_handle()
151                  || die "Can't get a language handle";
152               }
153               return $lh;
154             }
155
156       ·   $lh = YourProjClass::langname->new();
157
158           This constructs a language handle.  You usually don't call this
159           directly, but instead let "get_handle" find a language class to
160           "use" and to then call ->new on.
161
162       ·   $lh->init();
163
164           This is called by ->new to initialize newly-constructed language
165           handles.  If you define an init method in your class, remember that
166           it's usually considered a good idea to call $lh->SUPER::init in it
167           (presumably at the beginning), so that all classes get a chance to
168           initialize a new object however they see fit.
169
170       ·   YourProjClass->fallback_languages()
171
172           "get_handle" appends the return value of this to the end of
173           whatever list of languages you pass "get_handle".  Unless you
174           override this method, your project class will inherit
175           Locale::Maketext's "fallback_languages", which currently returns
176           "('i-default', 'en', 'en-US')".  ("i-default" is defined in RFC
177           2277).
178
179           This method (by having it return the name of a language-tag that
180           has an existing language class) can be used for making sure that
181           "get_handle" will always manage to construct a language handle
182           (assuming your language classes are in an appropriate @INC
183           directory).  Or you can use the next method:
184
185       ·   YourProjClass->fallback_language_classes()
186
187           "get_handle" appends the return value of this to the end of the
188           list of classes it will try using.  Unless you override this
189           method, your project class will inherit Locale::Maketext's
190           "fallback_language_classes", which currently returns an empty list,
191           "()".  By setting this to some value (namely, the name of a
192           loadable language class), you can be sure that "get_handle" will
193           always manage to construct a language handle.
194
195   The "maketext" Method
196       This is the most important method in Locale::Maketext:
197
198           $text = $lh->maketext(I<key>, ...parameters for this phrase...);
199
200       This looks in the %Lexicon of the language handle $lh and all its
201       superclasses, looking for an entry whose key is the string key.
202       Assuming such an entry is found, various things then happen, depending
203       on the value found:
204
205       If the value is a scalarref, the scalar is dereferenced and returned
206       (and any parameters are ignored).
207
208       If the value is a coderef, we return &$value($lh, ...parameters...).
209
210       If the value is a string that doesn't look like it's in Bracket
211       Notation, we return it (after replacing it with a scalarref, in its
212       %Lexicon).
213
214       If the value does look like it's in Bracket Notation, then we compile
215       it into a sub, replace the string in the %Lexicon with the new coderef,
216       and then we return &$new_sub($lh, ...parameters...).
217
218       Bracket Notation is discussed in a later section.  Note that trying to
219       compile a string into Bracket Notation can throw an exception if the
220       string is not syntactically valid (say, by not balancing brackets
221       right.)
222
223       Also, calling &$coderef($lh, ...parameters...) can throw any sort of
224       exception (if, say, code in that sub tries to divide by zero).  But a
225       very common exception occurs when you have Bracket Notation text that
226       says to call a method "foo", but there is no such method.  (E.g., "You
227       have [quatn,_1,ball]." will throw an exception on trying to call
228       $lh->quatn($_[1],'ball') -- you presumably meant "quant".)  "maketext"
229       catches these exceptions, but only to make the error message more
230       readable, at which point it rethrows the exception.
231
232       An exception may be thrown if key is not found in any of $lh's %Lexicon
233       hashes.  What happens if a key is not found, is discussed in a later
234       section, "Controlling Lookup Failure".
235
236       Note that you might find it useful in some cases to override the
237       "maketext" method with an "after method", if you want to translate
238       encodings, or even scripts:
239
240           package YrProj::zh_cn; # Chinese with PRC-style glyphs
241           use base ('YrProj::zh_tw');  # Taiwan-style
242           sub maketext {
243             my $self = shift(@_);
244             my $value = $self->maketext(@_);
245             return Chineeze::taiwan2mainland($value);
246           }
247
248       Or you may want to override it with something that traps any
249       exceptions, if that's critical to your program:
250
251         sub maketext {
252           my($lh, @stuff) = @_;
253           my $out;
254           eval { $out = $lh->SUPER::maketext(@stuff) };
255           return $out unless $@;
256           ...otherwise deal with the exception...
257         }
258
259       Other than those two situations, I don't imagine that it's useful to
260       override the "maketext" method.  (If you run into a situation where it
261       is useful, I'd be interested in hearing about it.)
262
263       $lh->fail_with or $lh->fail_with(PARAM)
264       $lh->failure_handler_auto
265           These two methods are discussed in the section "Controlling Lookup
266           Failure".
267
268       $lh->blacklist(@list)
269       $lh->whitelist(@list)
270           These methods are discussed in the section "Bracket Notation
271           Security".
272
273   Utility Methods
274       These are methods that you may find it handy to use, generally from
275       %Lexicon routines of yours (whether expressed as Bracket Notation or
276       not).
277
278       $language->quant($number, $singular)
279       $language->quant($number, $singular, $plural)
280       $language->quant($number, $singular, $plural, $negative)
281           This is generally meant to be called from inside Bracket Notation
282           (which is discussed later), as in
283
284                "Your search matched [quant,_1,document]!"
285
286           It's for quantifying a noun (i.e., saying how much of it there is,
287           while giving the correct form of it).  The behavior of this method
288           is handy for English and a few other Western European languages,
289           and you should override it for languages where it's not suitable.
290           You can feel free to read the source, but the current
291           implementation is basically as this pseudocode describes:
292
293                if $number is 0 and there's a $negative,
294                   return $negative;
295                elsif $number is 1,
296                   return "1 $singular";
297                elsif there's a $plural,
298                   return "$number $plural";
299                else
300                   return "$number " . $singular . "s";
301                #
302                # ...except that we actually call numf to
303                #  stringify $number before returning it.
304
305           So for English (with Bracket Notation) "...[quant,_1,file]..." is
306           fine (for 0 it returns "0 files", for 1 it returns "1 file", and
307           for more it returns "2 files", etc.)
308
309           But for "directory", you'd want "[quant,_1,directory,directories]"
310           so that our elementary "quant" method doesn't think that the plural
311           of "directory" is "directorys".  And you might find that the output
312           may sound better if you specify a negative form, as in:
313
314                "[quant,_1,file,files,No files] matched your query.\n"
315
316           Remember to keep in mind verb agreement (or adjectives too, in
317           other languages), as in:
318
319                "[quant,_1,document] were matched.\n"
320
321           Because if _1 is one, you get "1 document were matched".  An
322           acceptable hack here is to do something like this:
323
324                "[quant,_1,document was, documents were] matched.\n"
325
326       $language->numf($number)
327           This returns the given number formatted nicely according to this
328           language's conventions.  Maketext's default method is mostly to
329           just take the normal string form of the number (applying sprintf
330           "%G" for only very large numbers), and then to add commas as
331           necessary.  (Except that we apply "tr/,./.,/" if
332           $language->{'numf_comma'} is true; that's a bit of a hack that's
333           useful for languages that express two million as "2.000.000" and
334           not as "2,000,000").
335
336           If you want anything fancier, consider overriding this with
337           something that uses Number::Format, or does something else
338           entirely.
339
340           Note that numf is called by quant for stringifying all quantifying
341           numbers.
342
343       $language->numerate($number, $singular, $plural, $negative)
344           This returns the given noun form which is appropriate for the
345           quantity $number according to this language's conventions.
346           "numerate" is used internally by "quant" to quantify nouns.  Use it
347           directly -- usually from bracket notation -- to avoid "quant"'s
348           implicit call to "numf" and output of a numeric quantity.
349
350       $language->sprintf($format, @items)
351           This is just a wrapper around Perl's normal "sprintf" function.
352           It's provided so that you can use "sprintf" in Bracket Notation:
353
354                "Couldn't access datanode [sprintf,%10x=~[%s~],_1,_2]!\n"
355
356           returning...
357
358                Couldn't access datanode      Stuff=[thangamabob]!
359
360       $language->language_tag()
361           Currently this just takes the last bit of "ref($language)", turns
362           underscores to dashes, and returns it.  So if $language is an
363           object of class Hee::HOO::Haw::en_us, $language->language_tag()
364           returns "en-us".  (Yes, the usual representation for that language
365           tag is "en-US", but case is never considered meaningful in
366           language-tag comparison.)
367
368           You may override this as you like; Maketext doesn't use it for
369           anything.
370
371       $language->encoding()
372           Currently this isn't used for anything, but it's provided (with
373           default value of "(ref($language) && $language->{'encoding'})) or
374           "iso-8859-1"" ) as a sort of suggestion that it may be
375           useful/necessary to associate encodings with your language handles
376           (whether on a per-class or even per-handle basis.)
377
378   Language Handle Attributes and Internals
379       A language handle is a flyweight object -- i.e., it doesn't
380       (necessarily) carry any data of interest, other than just being a
381       member of whatever class it belongs to.
382
383       A language handle is implemented as a blessed hash.  Subclasses of
384       yours can store whatever data you want in the hash.  Currently the only
385       hash entry used by any crucial Maketext method is "fail", so feel free
386       to use anything else as you like.
387
388       Remember: Don't be afraid to read the Maketext source if there's any
389       point on which this documentation is unclear.  This documentation is
390       vastly longer than the module source itself.
391

LANGUAGE CLASS HIERARCHIES

393       These are Locale::Maketext's assumptions about the class hierarchy
394       formed by all your language classes:
395
396       ·   You must have a project base class, which you load, and which you
397           then use as the first argument in the call to
398           YourProjClass->get_handle(...).  It should derive (whether directly
399           or indirectly) from Locale::Maketext.  It doesn't matter how you
400           name this class, although assuming this is the localization
401           component of your Super Mega Program, good names for your project
402           class might be SuperMegaProgram::Localization,
403           SuperMegaProgram::L10N, SuperMegaProgram::I18N,
404           SuperMegaProgram::International, or even
405           SuperMegaProgram::Languages or SuperMegaProgram::Messages.
406
407       ·   Language classes are what YourProjClass->get_handle will try to
408           load.  It will look for them by taking each language-tag (skipping
409           it if it doesn't look like a language-tag or locale-tag!), turning
410           it to all lowercase, turning dashes to underscores, and appending
411           it to YourProjClass . "::".  So this:
412
413             $lh = YourProjClass->get_handle(
414               'en-US', 'fr', 'kon', 'i-klingon', 'i-klingon-romanized'
415             );
416
417           will try loading the classes YourProjClass::en_us (note
418           lowercase!), YourProjClass::fr, YourProjClass::kon,
419           YourProjClass::i_klingon and YourProjClass::i_klingon_romanized.
420           (And it'll stop at the first one that actually loads.)
421
422       ·   I assume that each language class derives (directly or indirectly)
423           from your project class, and also defines its @ISA, its %Lexicon,
424           or both.  But I anticipate no dire consequences if these
425           assumptions do not hold.
426
427       ·   Language classes may derive from other language classes (although
428           they should have "use Thatclassname" or "use base
429           qw(...classes...)").  They may derive from the project class.  They
430           may derive from some other class altogether.  Or via multiple
431           inheritance, it may derive from any mixture of these.
432
433       ·   I foresee no problems with having multiple inheritance in your
434           hierarchy of language classes.  (As usual, however, Perl will
435           complain bitterly if you have a cycle in the hierarchy: i.e., if
436           any class is its own ancestor.)
437

ENTRIES IN EACH LEXICON

439       A typical %Lexicon entry is meant to signify a phrase, taking some
440       number (0 or more) of parameters.  An entry is meant to be accessed by
441       via a string key in $lh->maketext(key, ...parameters...), which should
442       return a string that is generally meant for be used for "output" to the
443       user -- regardless of whether this actually means printing to STDOUT,
444       writing to a file, or putting into a GUI widget.
445
446       While the key must be a string value (since that's a basic restriction
447       that Perl places on hash keys), the value in the lexicon can currently
448       be of several types: a defined scalar, scalarref, or coderef.  The use
449       of these is explained above, in the section 'The "maketext" Method',
450       and Bracket Notation for strings is discussed in the next section.
451
452       While you can use arbitrary unique IDs for lexicon keys (like
453       "_min_larger_max_error"), it is often useful for if an entry's key is
454       itself a valid value, like this example error message:
455
456         "Minimum ([_1]) is larger than maximum ([_2])!\n",
457
458       Compare this code that uses an arbitrary ID...
459
460         die $lh->maketext( "_min_larger_max_error", $min, $max )
461          if $min > $max;
462
463       ...to this code that uses a key-as-value:
464
465         die $lh->maketext(
466          "Minimum ([_1]) is larger than maximum ([_2])!\n",
467          $min, $max
468         ) if $min > $max;
469
470       The second is, in short, more readable.  In particular, it's obvious
471       that the number of parameters you're feeding to that phrase (two) is
472       the number of parameters that it wants to be fed.  (Since you see _1
473       and a _2 being used in the key there.)
474
475       Also, once a project is otherwise complete and you start to localize
476       it, you can scrape together all the various keys you use, and pass it
477       to a translator; and then the translator's work will go faster if what
478       he's presented is this:
479
480        "Minimum ([_1]) is larger than maximum ([_2])!\n",
481         => "",   # fill in something here, Jacques!
482
483       rather than this more cryptic mess:
484
485        "_min_larger_max_error"
486         => "",   # fill in something here, Jacques
487
488       I think that keys as lexicon values makes the completed lexicon entries
489       more readable:
490
491        "Minimum ([_1]) is larger than maximum ([_2])!\n",
492         => "Le minimum ([_1]) est plus grand que le maximum ([_2])!\n",
493
494       Also, having valid values as keys becomes very useful if you set up an
495       _AUTO lexicon.  _AUTO lexicons are discussed in a later section.
496
497       I almost always use keys that are themselves valid lexicon values.  One
498       notable exception is when the value is quite long.  For example, to get
499       the screenful of data that a command-line program might return when
500       given an unknown switch, I often just use a brief, self-explanatory key
501       such as "_USAGE_MESSAGE".  At that point I then go and immediately to
502       define that lexicon entry in the ProjectClass::L10N::en lexicon (since
503       English is always my "project language"):
504
505         '_USAGE_MESSAGE' => <<'EOSTUFF',
506         ...long long message...
507         EOSTUFF
508
509       and then I can use it as:
510
511         getopt('oDI', \%opts) or die $lh->maketext('_USAGE_MESSAGE');
512
513       Incidentally, note that each class's %Lexicon inherits-and-extends the
514       lexicons in its superclasses.  This is not because these are special
515       hashes per se, but because you access them via the "maketext" method,
516       which looks for entries across all the %Lexicon hashes in a language
517       class and all its ancestor classes.  (This is because the idea of
518       "class data" isn't directly implemented in Perl, but is instead left to
519       individual class-systems to implement as they see fit..)
520
521       Note that you may have things stored in a lexicon besides just phrases
522       for output:  for example, if your program takes input from the
523       keyboard, asking a "(Y/N)" question, you probably need to know what the
524       equivalent of "Y[es]/N[o]" is in whatever language.  You probably also
525       need to know what the equivalents of the answers "y" and "n" are.  You
526       can store that information in the lexicon (say, under the keys
527       "~answer_y" and "~answer_n", and the long forms as "~answer_yes" and
528       "~answer_no", where "~" is just an ad-hoc character meant to indicate
529       to programmers/translators that these are not phrases for output).
530
531       Or instead of storing this in the language class's lexicon, you can
532       (and, in some cases, really should) represent the same bit of knowledge
533       as code in a method in the language class.  (That leaves a tidy
534       distinction between the lexicon as the things we know how to say, and
535       the rest of the things in the lexicon class as things that we know how
536       to do.)  Consider this example of a processor for responses to French
537       "oui/non" questions:
538
539         sub y_or_n {
540           return undef unless defined $_[1] and length $_[1];
541           my $answer = lc $_[1];  # smash case
542           return 1 if $answer eq 'o' or $answer eq 'oui';
543           return 0 if $answer eq 'n' or $answer eq 'non';
544           return undef;
545         }
546
547       ...which you'd then call in a construct like this:
548
549         my $response;
550         until(defined $response) {
551           print $lh->maketext("Open the pod bay door (y/n)? ");
552           $response = $lh->y_or_n( get_input_from_keyboard_somehow() );
553         }
554         if($response) { $pod_bay_door->open()         }
555         else          { $pod_bay_door->leave_closed() }
556
557       Other data worth storing in a lexicon might be things like filenames
558       for language-targetted resources:
559
560         ...
561         "_main_splash_png"
562           => "/styles/en_us/main_splash.png",
563         "_main_splash_imagemap"
564           => "/styles/en_us/main_splash.incl",
565         "_general_graphics_path"
566           => "/styles/en_us/",
567         "_alert_sound"
568           => "/styles/en_us/hey_there.wav",
569         "_forward_icon"
570          => "left_arrow.png",
571         "_backward_icon"
572          => "right_arrow.png",
573         # In some other languages, left equals
574         #  BACKwards, and right is FOREwards.
575         ...
576
577       You might want to do the same thing for expressing key bindings or the
578       like (since hardwiring "q" as the binding for the function that quits a
579       screen/menu/program is useful only if your language happens to
580       associate "q" with "quit"!)
581

BRACKET NOTATION

583       Bracket Notation is a crucial feature of Locale::Maketext.  I mean
584       Bracket Notation to provide a replacement for the use of sprintf
585       formatting.  Everything you do with Bracket Notation could be done with
586       a sub block, but bracket notation is meant to be much more concise.
587
588       Bracket Notation is a like a miniature "template" system (in the sense
589       of Text::Template, not in the sense of C++ templates), where normal
590       text is passed thru basically as is, but text in special regions is
591       specially interpreted.  In Bracket Notation, you use square brackets
592       ("[...]"), not curly braces ("{...}") to note sections that are
593       specially interpreted.
594
595       For example, here all the areas that are taken literally are underlined
596       with a "^", and all the in-bracket special regions are underlined with
597       an X:
598
599         "Minimum ([_1]) is larger than maximum ([_2])!\n",
600          ^^^^^^^^^ XX ^^^^^^^^^^^^^^^^^^^^^^^^^^ XX ^^^^
601
602       When that string is compiled from bracket notation into a real Perl
603       sub, it's basically turned into:
604
605         sub {
606           my $lh = $_[0];
607           my @params = @_;
608           return join '',
609             "Minimum (",
610             ...some code here...
611             ") is larger than maximum (",
612             ...some code here...
613             ")!\n",
614         }
615         # to be called by $lh->maketext(KEY, params...)
616
617       In other words, text outside bracket groups is turned into string
618       literals.  Text in brackets is rather more complex, and currently
619       follows these rules:
620
621       ·   Bracket groups that are empty, or which consist only of whitespace,
622           are ignored.  (Examples: "[]", "[    ]", or a [ and a ] with
623           returns and/or tabs and/or spaces between them.
624
625           Otherwise, each group is taken to be a comma-separated group of
626           items, and each item is interpreted as follows:
627
628       ·   An item that is "_digits" or "_-digits" is interpreted as
629           $_[value].  I.e., "_1" becomes with $_[1], and "_-3" is interpreted
630           as $_[-3] (in which case @_ should have at least three elements in
631           it).  Note that $_[0] is the language handle, and is typically not
632           named directly.
633
634       ·   An item "_*" is interpreted to mean "all of @_ except $_[0]".
635           I.e., @_[1..$#_].  Note that this is an empty list in the case of
636           calls like $lh->maketext(key) where there are no parameters (except
637           $_[0], the language handle).
638
639       ·   Otherwise, each item is interpreted as a string literal.
640
641       The group as a whole is interpreted as follows:
642
643       ·   If the first item in a bracket group looks like a method name, then
644           that group is interpreted like this:
645
646             $lh->that_method_name(
647               ...rest of items in this group...
648             ),
649
650       ·   If the first item in a bracket group is "*", it's taken as
651           shorthand for the so commonly called "quant" method.  Similarly, if
652           the first item in a bracket group is "#", it's taken to be
653           shorthand for "numf".
654
655       ·   If the first item in a bracket group is the empty-string, or "_*"
656           or "_digits" or "_-digits", then that group is interpreted as just
657           the interpolation of all its items:
658
659             join('',
660               ...rest of items in this group...
661             ),
662
663           Examples:  "[_1]" and "[,_1]", which are synonymous; and
664           ""[,ID-(,_4,-,_2,)]"", which compiles as "join "", "ID-(", $_[4],
665           "-", $_[2], ")"".
666
667       ·   Otherwise this bracket group is invalid.  For example, in the group
668           "[!@#,whatever]", the first item "!@#" is neither the empty-string,
669           "_number", "_-number", "_*", nor a valid method name; and so
670           Locale::Maketext will throw an exception of you try compiling an
671           expression containing this bracket group.
672
673       Note, incidentally, that items in each group are comma-separated, not
674       "/\s*,\s*/"-separated.  That is, you might expect that this bracket
675       group:
676
677         "Hoohah [foo, _1 , bar ,baz]!"
678
679       would compile to this:
680
681         sub {
682           my $lh = $_[0];
683           return join '',
684             "Hoohah ",
685             $lh->foo( $_[1], "bar", "baz"),
686             "!",
687         }
688
689       But it actually compiles as this:
690
691         sub {
692           my $lh = $_[0];
693           return join '',
694             "Hoohah ",
695             $lh->foo(" _1 ", " bar ", "baz"),  # note the <space> in " bar "
696             "!",
697         }
698
699       In the notation discussed so far, the characters "[" and "]" are given
700       special meaning, for opening and closing bracket groups, and "," has a
701       special meaning inside bracket groups, where it separates items in the
702       group.  This begs the question of how you'd express a literal "[" or
703       "]" in a Bracket Notation string, and how you'd express a literal comma
704       inside a bracket group.  For this purpose I've adopted "~" (tilde) as
705       an escape character:  "~[" means a literal '[' character anywhere in
706       Bracket Notation (i.e., regardless of whether you're in a bracket group
707       or not), and ditto for "~]" meaning a literal ']', and "~," meaning a
708       literal comma.  (Altho "," means a literal comma outside of bracket
709       groups -- it's only inside bracket groups that commas are special.)
710
711       And on the off chance you need a literal tilde in a bracket expression,
712       you get it with "~~".
713
714       Currently, an unescaped "~" before a character other than a bracket or
715       a comma is taken to mean just a "~" and that character.  I.e., "~X"
716       means the same as "~~X" -- i.e., one literal tilde, and then one
717       literal "X".  However, by using "~X", you are assuming that no future
718       version of Maketext will use "~X" as a magic escape sequence.  In
719       practice this is not a great problem, since first off you can just
720       write "~~X" and not worry about it; second off, I doubt I'll add lots
721       of new magic characters to bracket notation; and third off, you aren't
722       likely to want literal "~" characters in your messages anyway, since
723       it's not a character with wide use in natural language text.
724
725       Brackets must be balanced -- every openbracket must have one matching
726       closebracket, and vice versa.  So these are all invalid:
727
728         "I ate [quant,_1,rhubarb pie."
729         "I ate [quant,_1,rhubarb pie[."
730         "I ate quant,_1,rhubarb pie]."
731         "I ate quant,_1,rhubarb pie[."
732
733       Currently, bracket groups do not nest.  That is, you cannot say:
734
735         "Foo [bar,baz,[quux,quuux]]\n";
736
737       If you need a notation that's that powerful, use normal Perl:
738
739         %Lexicon = (
740           ...
741           "some_key" => sub {
742             my $lh = $_[0];
743             join '',
744               "Foo ",
745               $lh->bar('baz', $lh->quux('quuux')),
746               "\n",
747           },
748           ...
749         );
750
751       Or write the "bar" method so you don't need to pass it the output from
752       calling quux.
753
754       I do not anticipate that you will need (or particularly want) to nest
755       bracket groups, but you are welcome to email me with convincing (real-
756       life) arguments to the contrary.
757

BRACKET NOTATION SECURITY

759       Locale::Maketext does not use any special syntax to differentiate
760       bracket notation methods from normal class or object methods. This
761       design makes it vulnerable to format string attacks whenever it is used
762       to process strings provided by untrusted users.
763
764       Locale::Maketext does support blacklist and whitelist functionality to
765       limit which methods may be called as bracket notation methods.
766
767       By default, Locale::Maketext blacklists all methods in the
768       Locale::Maketext namespace that begin with the '_' character, and all
769       methods which include Perl's namespace separator characters.
770
771       The default blacklist for Locale::Maketext also prevents use of the
772       following methods in bracket notation:
773
774         blacklist
775         encoding
776         fail_with
777         failure_handler_auto
778         fallback_language_classes
779         fallback_languages
780         get_handle
781         init
782         language_tag
783         maketext
784         new
785         whitelist
786
787       This list can be extended by either blacklisting additional "known bad"
788       methods, or whitelisting only "known good" methods.
789
790       To prevent specific methods from being called in bracket notation, use
791       the blacklist() method:
792
793         my $lh = MyProgram::L10N->get_handle();
794         $lh->blacklist(qw{my_internal_method my_other_method});
795         $lh->maketext('[my_internal_method]'); # dies
796
797       To limit the allowed bracked notation methods to a specific list, use
798       the whitelist() method:
799
800         my $lh = MyProgram::L10N->get_handle();
801         $lh->whitelist('numerate', 'numf');
802         $lh->maketext('[_1] [numerate, _1,shoe,shoes]', 12); # works
803         $lh->maketext('[my_internal_method]'); # dies
804
805       The blacklist() and whitelist() methods extend their internal lists
806       whenever they are called. To reset the blacklist or whitelist, create a
807       new maketext object.
808
809         my $lh = MyProgram::L10N->get_handle();
810         $lh->blacklist('numerate');
811         $lh->blacklist('numf');
812         $lh->maketext('[_1] [numerate,_1,shoe,shoes]', 12); # dies
813
814       For lexicons that use an internal cache, translations which have
815       already been cached in their compiled form are not affected by
816       subsequent changes to the whitelist or blacklist settings. Lexicons
817       that use an external cache will have their cache cleared whenever the
818       whitelist of blacklist setings change.  The difference between the two
819       types of caching is explained in the "Readonly Lexicons" section.
820
821       Methods disallowed by the blacklist cannot be permitted by the
822       whitelist.
823

AUTO LEXICONS

825       If maketext goes to look in an individual %Lexicon for an entry for key
826       (where key does not start with an underscore), and sees none, but does
827       see an entry of "_AUTO" => some_true_value, then we actually define
828       $Lexicon{key} = key right then and there, and then use that value as if
829       it had been there all along.  This happens before we even look in any
830       superclass %Lexicons!
831
832       (This is meant to be somewhat like the AUTOLOAD mechanism in Perl's
833       function call system -- or, looked at another way, like the AutoLoader
834       module.)
835
836       I can picture all sorts of circumstances where you just do not want
837       lookup to be able to fail (since failing normally means that maketext
838       throws a "die", although see the next section for greater control over
839       that).  But here's one circumstance where _AUTO lexicons are meant to
840       be especially useful:
841
842       As you're writing an application, you decide as you go what messages
843       you need to emit.  Normally you'd go to write this:
844
845         if(-e $filename) {
846           go_process_file($filename)
847         } else {
848           print qq{Couldn't find file "$filename"!\n};
849         }
850
851       but since you anticipate localizing this, you write:
852
853         use ThisProject::I18N;
854         my $lh = ThisProject::I18N->get_handle();
855          # For the moment, assume that things are set up so
856          # that we load class ThisProject::I18N::en
857          # and that that's the class that $lh belongs to.
858         ...
859         if(-e $filename) {
860           go_process_file($filename)
861         } else {
862           print $lh->maketext(
863             qq{Couldn't find file "[_1]"!\n}, $filename
864           );
865         }
866
867       Now, right after you've just written the above lines, you'd normally
868       have to go open the file ThisProject/I18N/en.pm, and immediately add an
869       entry:
870
871         "Couldn't find file \"[_1]\"!\n"
872         => "Couldn't find file \"[_1]\"!\n",
873
874       But I consider that somewhat of a distraction from the work of getting
875       the main code working -- to say nothing of the fact that I often have
876       to play with the program a few times before I can decide exactly what
877       wording I want in the messages (which in this case would require me to
878       go changing three lines of code: the call to maketext with that key,
879       and then the two lines in ThisProject/I18N/en.pm).
880
881       However, if you set "_AUTO => 1" in the %Lexicon in,
882       ThisProject/I18N/en.pm (assuming that English (en) is the language that
883       all your programmers will be using for this project's internal message
884       keys), then you don't ever have to go adding lines like this
885
886         "Couldn't find file \"[_1]\"!\n"
887         => "Couldn't find file \"[_1]\"!\n",
888
889       to ThisProject/I18N/en.pm, because if _AUTO is true there, then just
890       looking for an entry with the key "Couldn't find file \"[_1]\"!\n" in
891       that lexicon will cause it to be added, with that value!
892
893       Note that the reason that keys that start with "_" are immune to _AUTO
894       isn't anything generally magical about the underscore character -- I
895       just wanted a way to have most lexicon keys be autoable, except for
896       possibly a few, and I arbitrarily decided to use a leading underscore
897       as a signal to distinguish those few.
898

READONLY LEXICONS

900       If your lexicon is a tied hash the simple act of caching the compiled
901       value can be fatal.
902
903       For example a GDBM_File GDBM_READER tied hash will die with something
904       like:
905
906          gdbm store returned -1, errno 2, key "..." at ...
907
908       All you need to do is turn on caching outside of the lexicon hash
909       itself like so:
910
911          sub init {
912              my ($lh) = @_;
913              ...
914              $lh->{'use_external_lex_cache'} = 1;
915              ...
916          }
917
918       And then instead of storing the compiled value in the lexicon hash it
919       will store it in $lh->{'_external_lex_cache'}
920

CONTROLLING LOOKUP FAILURE

922       If you call $lh->maketext(key, ...parameters...), and there's no entry
923       key in $lh's class's %Lexicon, nor in the superclass %Lexicon hash, and
924       if we can't auto-make key (because either it starts with a "_", or
925       because none of its lexicons have "_AUTO => 1,"), then we have failed
926       to find a normal way to maketext key.  What then happens in these
927       failure conditions, depends on the $lh object's "fail" attribute.
928
929       If the language handle has no "fail" attribute, maketext will simply
930       throw an exception (i.e., it calls "die", mentioning the key whose
931       lookup failed, and naming the line number where the calling
932       $lh->maketext(key,...) was.
933
934       If the language handle has a "fail" attribute whose value is a coderef,
935       then $lh->maketext(key,...params...) gives up and calls:
936
937         return $that_subref->($lh, $key, @params);
938
939       Otherwise, the "fail" attribute's value should be a string denoting a
940       method name, so that $lh->maketext(key,...params...) can give up with:
941
942         return $lh->$that_method_name($phrase, @params);
943
944       The "fail" attribute can be accessed with the "fail_with" method:
945
946         # Set to a coderef:
947         $lh->fail_with( \&failure_handler );
948
949         # Set to a method name:
950         $lh->fail_with( 'failure_method' );
951
952         # Set to nothing (i.e., so failure throws a plain exception)
953         $lh->fail_with( undef );
954
955         # Get the current value
956         $handler = $lh->fail_with();
957
958       Now, as to what you may want to do with these handlers:  Maybe you'd
959       want to log what key failed for what class, and then die.  Maybe you
960       don't like "die" and instead you want to send the error message to
961       STDOUT (or wherever) and then merely "exit()".
962
963       Or maybe you don't want to "die" at all!  Maybe you could use a handler
964       like this:
965
966         # Make all lookups fall back onto an English value,
967         #  but only after we log it for later fingerpointing.
968         my $lh_backup = ThisProject->get_handle('en');
969         open(LEX_FAIL_LOG, ">>wherever/lex.log") || die "GNAARGH $!";
970         sub lex_fail {
971           my($failing_lh, $key, $params) = @_;
972           print LEX_FAIL_LOG scalar(localtime), "\t",
973              ref($failing_lh), "\t", $key, "\n";
974           return $lh_backup->maketext($key,@params);
975         }
976
977       Some users have expressed that they think this whole mechanism of
978       having a "fail" attribute at all, seems a rather pointless
979       complication.  But I want Locale::Maketext to be usable for software
980       projects of any scale and type; and different software projects have
981       different ideas of what the right thing is to do in failure conditions.
982       I could simply say that failure always throws an exception, and that if
983       you want to be careful, you'll just have to wrap every call to
984       $lh->maketext in an eval { }.  However, I want programmers to reserve
985       the right (via the "fail" attribute) to treat lookup failure as
986       something other than an exception of the same level of severity as a
987       config file being unreadable, or some essential resource being
988       inaccessible.
989
990       One possibly useful value for the "fail" attribute is the method name
991       "failure_handler_auto".  This is a method defined in the class
992       Locale::Maketext itself.  You set it with:
993
994         $lh->fail_with('failure_handler_auto');
995
996       Then when you call $lh->maketext(key, ...parameters...) and there's no
997       key in any of those lexicons, maketext gives up with
998
999         return $lh->failure_handler_auto($key, @params);
1000
1001       But failure_handler_auto, instead of dying or anything, compiles $key,
1002       caching it in
1003
1004           $lh->{'failure_lex'}{$key} = $compiled
1005
1006       and then calls the compiled value, and returns that.  (I.e., if $key
1007       looks like bracket notation, $compiled is a sub, and we return
1008       &{$compiled}(@params); but if $key is just a plain string, we just
1009       return that.)
1010
1011       The effect of using "failure_auto_handler" is like an AUTO lexicon,
1012       except that it 1) compiles $key even if it starts with "_", and 2) you
1013       have a record in the new hashref $lh->{'failure_lex'} of all the keys
1014       that have failed for this object.  This should avoid your program dying
1015       -- as long as your keys aren't actually invalid as bracket code, and as
1016       long as they don't try calling methods that don't exist.
1017
1018       "failure_auto_handler" may not be exactly what you want, but I hope it
1019       at least shows you that maketext failure can be mitigated in any number
1020       of very flexible ways.  If you can formalize exactly what you want, you
1021       should be able to express that as a failure handler.  You can even make
1022       it default for every object of a given class, by setting it in that
1023       class's init:
1024
1025         sub init {
1026           my $lh = $_[0];  # a newborn handle
1027           $lh->SUPER::init();
1028           $lh->fail_with('my_clever_failure_handler');
1029           return;
1030         }
1031         sub my_clever_failure_handler {
1032           ...you clever things here...
1033         }
1034

HOW TO USE MAKETEXT

1036       Here is a brief checklist on how to use Maketext to localize
1037       applications:
1038
1039       ·   Decide what system you'll use for lexicon keys.  If you insist, you
1040           can use opaque IDs (if you're nostalgic for "catgets"), but I have
1041           better suggestions in the section "Entries in Each Lexicon", above.
1042           Assuming you opt for meaningful keys that double as values (like
1043           "Minimum ([_1]) is larger than maximum ([_2])!\n"), you'll have to
1044           settle on what language those should be in.  For the sake of
1045           argument, I'll call this English, specifically American English,
1046           "en-US".
1047
1048       ·   Create a class for your localization project.  This is the name of
1049           the class that you'll use in the idiom:
1050
1051             use Projname::L10N;
1052             my $lh = Projname::L10N->get_handle(...) || die "Language?";
1053
1054           Assuming you call your class Projname::L10N, create a class
1055           consisting minimally of:
1056
1057             package Projname::L10N;
1058             use base qw(Locale::Maketext);
1059             ...any methods you might want all your languages to share...
1060
1061             # And, assuming you want the base class to be an _AUTO lexicon,
1062             # as is discussed a few sections up:
1063
1064             1;
1065
1066       ·   Create a class for the language your internal keys are in.  Name
1067           the class after the language-tag for that language, in lowercase,
1068           with dashes changed to underscores.  Assuming your project's first
1069           language is US English, you should call this Projname::L10N::en_us.
1070           It should consist minimally of:
1071
1072             package Projname::L10N::en_us;
1073             use base qw(Projname::L10N);
1074             %Lexicon = (
1075               '_AUTO' => 1,
1076             );
1077             1;
1078
1079           (For the rest of this section, I'll assume that this "first
1080           language class" of Projname::L10N::en_us has _AUTO lexicon.)
1081
1082       ·   Go and write your program.  Everywhere in your program where you
1083           would say:
1084
1085             print "Foobar $thing stuff\n";
1086
1087           instead do it thru maketext, using no variable interpolation in the
1088           key:
1089
1090             print $lh->maketext("Foobar [_1] stuff\n", $thing);
1091
1092           If you get tired of constantly saying "print $lh->maketext",
1093           consider making a functional wrapper for it, like so:
1094
1095             use Projname::L10N;
1096             use vars qw($lh);
1097             $lh = Projname::L10N->get_handle(...) || die "Language?";
1098             sub pmt (@) { print( $lh->maketext(@_)) }
1099              # "pmt" is short for "Print MakeText"
1100             $Carp::Verbose = 1;
1101              # so if maketext fails, we see made the call to pmt
1102
1103           Besides whole phrases meant for output, anything language-dependent
1104           should be put into the class Projname::L10N::en_us, whether as
1105           methods, or as lexicon entries -- this is discussed in the section
1106           "Entries in Each Lexicon", above.
1107
1108       ·   Once the program is otherwise done, and once its localization for
1109           the first language works right (via the data and methods in
1110           Projname::L10N::en_us), you can get together the data for
1111           translation.  If your first language lexicon isn't an _AUTO
1112           lexicon, then you already have all the messages explicitly in the
1113           lexicon (or else you'd be getting exceptions thrown when you call
1114           $lh->maketext to get messages that aren't in there).  But if you
1115           were (advisedly) lazy and are using an _AUTO lexicon, then you've
1116           got to make a list of all the phrases that you've so far been
1117           letting _AUTO generate for you.  There are very many ways to
1118           assemble such a list.  The most straightforward is to simply grep
1119           the source for every occurrence of "maketext" (or calls to wrappers
1120           around it, like the above "pmt" function), and to log the following
1121           phrase.
1122
1123       ·   You may at this point want to consider whether your base class
1124           (Projname::L10N), from which all lexicons inherit from
1125           (Projname::L10N::en, Projname::L10N::es, etc.), should be an _AUTO
1126           lexicon.  It may be true that in theory, all needed messages will
1127           be in each language class; but in the presumably unlikely or
1128           "impossible" case of lookup failure, you should consider whether
1129           your program should throw an exception, emit text in English (or
1130           whatever your project's first language is), or some more complex
1131           solution as described in the section "Controlling Lookup Failure",
1132           above.
1133
1134       ·   Submit all messages/phrases/etc. to translators.
1135
1136           (You may, in fact, want to start with localizing to one other
1137           language at first, if you're not sure that you've properly
1138           abstracted the language-dependent parts of your code.)
1139
1140           Translators may request clarification of the situation in which a
1141           particular phrase is found.  For example, in English we are
1142           entirely happy saying "n files found", regardless of whether we
1143           mean "I looked for files, and found n of them" or the rather
1144           distinct situation of "I looked for something else (like lines in
1145           files), and along the way I saw n files."  This may involve
1146           rethinking things that you thought quite clear: should "Edit" on a
1147           toolbar be a noun ("editing") or a verb ("to edit")?  Is there
1148           already a conventionalized way to express that menu option,
1149           separate from the target language's normal word for "to edit"?
1150
1151           In all cases where the very common phenomenon of quantification
1152           (saying "N files", for any value of N) is involved, each translator
1153           should make clear what dependencies the number causes in the
1154           sentence.  In many cases, dependency is limited to words adjacent
1155           to the number, in places where you might expect them ("I found
1156           the-?PLURAL N empty-?PLURAL directory-?PLURAL"), but in some cases
1157           there are unexpected dependencies ("I found-?PLURAL ..."!) as well
1158           as long-distance dependencies "The N directory-?PLURAL could not be
1159           deleted-?PLURAL"!).
1160
1161           Remind the translators to consider the case where N is 0: "0 files
1162           found" isn't exactly natural-sounding in any language, but it may
1163           be unacceptable in many -- or it may condition special kinds of
1164           agreement (similar to English "I didN'T find ANY files").
1165
1166           Remember to ask your translators about numeral formatting in their
1167           language, so that you can override the "numf" method as
1168           appropriate.  Typical variables in number formatting are:  what to
1169           use as a decimal point (comma? period?); what to use as a thousands
1170           separator (space? nonbreaking space? comma? period? small middot?
1171           prime? apostrophe?); and even whether the so-called "thousands
1172           separator" is actually for every third digit -- I've heard reports
1173           of two hundred thousand being expressible as "2,00,000" for some
1174           Indian (Subcontinental) languages, besides the less surprising
1175           "200 000", "200.000", "200,000", and "200'000".  Also, using a set
1176           of numeral glyphs other than the usual ASCII "0"-"9" might be
1177           appreciated, as via "tr/0-9/\x{0966}-\x{096F}/" for getting digits
1178           in Devanagari script (for Hindi, Konkani, others).
1179
1180           The basic "quant" method that Locale::Maketext provides should be
1181           good for many languages.  For some languages, it might be useful to
1182           modify it (or its constituent "numerate" method) to take a plural
1183           form in the two-argument call to "quant" (as in "[quant,_1,files]")
1184           if it's all-around easier to infer the singular form from the
1185           plural, than to infer the plural form from the singular.
1186
1187           But for other languages (as is discussed at length in
1188           Locale::Maketext::TPJ13), simple "quant"/"numf" is not enough.  For
1189           the particularly problematic Slavic languages, what you may need is
1190           a method which you provide with the number, the citation form of
1191           the noun to quantify, and the case and gender that the sentence's
1192           syntax projects onto that noun slot.  The method would then be
1193           responsible for determining what grammatical number that numeral
1194           projects onto its noun phrase, and what case and gender it may
1195           override the normal case and gender with; and then it would look up
1196           the noun in a lexicon providing all needed inflected forms.
1197
1198       ·   You may also wish to discuss with the translators the question of
1199           how to relate different subforms of the same language tag,
1200           considering how this reacts with "get_handle"'s treatment of these.
1201           For example, if a user accepts interfaces in "en, fr", and you have
1202           interfaces available in "en-US" and "fr", what should they get?
1203           You may wish to resolve this by establishing that "en" and "en-US"
1204           are effectively synonymous, by having one class zero-derive from
1205           the other.
1206
1207           For some languages this issue may never come up (Danish is rarely
1208           expressed as "da-DK", but instead is just "da").  And for other
1209           languages, the whole concept of a "generic" form may verge on being
1210           uselessly vague, particularly for interfaces involving voice media
1211           in forms of Arabic or Chinese.
1212
1213       ·   Once you've localized your program/site/etc. for all desired
1214           languages, be sure to show the result (whether live, or via
1215           screenshots) to the translators.  Once they approve, make every
1216           effort to have it then checked by at least one other speaker of
1217           that language.  This holds true even when (or especially when) the
1218           translation is done by one of your own programmers.  Some kinds of
1219           systems may be harder to find testers for than others, depending on
1220           the amount of domain-specific jargon and concepts involved -- it's
1221           easier to find people who can tell you whether they approve of your
1222           translation for "delete this message" in an email-via-Web
1223           interface, than to find people who can give you an informed opinion
1224           on your translation for "attribute value" in an XML query tool's
1225           interface.
1226

SEE ALSO

1228       I recommend reading all of these:
1229
1230       Locale::Maketext::TPJ13 -- my The Perl Journal article about Maketext.
1231       It explains many important concepts underlying Locale::Maketext's
1232       design, and some insight into why Maketext is better than the plain old
1233       approach of having message catalogs that are just databases of sprintf
1234       formats.
1235
1236       File::Findgrep is a sample application/module that uses
1237       Locale::Maketext to localize its messages.  For a larger
1238       internationalized system, see also Apache::MP3.
1239
1240       I18N::LangTags.
1241
1242       Win32::Locale.
1243
1244       RFC 3066, Tags for the Identification of Languages, as at
1245       http://sunsite.dk/RFC/rfc/rfc3066.html
1246
1247       RFC 2277, IETF Policy on Character Sets and Languages is at
1248       http://sunsite.dk/RFC/rfc/rfc2277.html -- much of it is just things of
1249       interest to protocol designers, but it explains some basic concepts,
1250       like the distinction between locales and language-tags.
1251
1252       The manual for GNU "gettext".  The gettext dist is available in
1253       "ftp://prep.ai.mit.edu/pub/gnu/" -- get a recent gettext tarball and
1254       look in its "doc/" directory, there's an easily browsable HTML version
1255       in there.  The gettext documentation asks lots of questions worth
1256       thinking about, even if some of their answers are sometimes wonky,
1257       particularly where they start talking about pluralization.
1258
1259       The Locale/Maketext.pm source.  Observe that the module is much shorter
1260       than its documentation!
1261
1263       Copyright (c) 1999-2004 Sean M. Burke.  All rights reserved.
1264
1265       This library is free software; you can redistribute it and/or modify it
1266       under the same terms as Perl itself.
1267
1268       This program is distributed in the hope that it will be useful, but
1269       without any warranty; without even the implied warranty of
1270       merchantability or fitness for a particular purpose.
1271

AUTHOR

1273       Sean M. Burke "sburke@cpan.org"
1274
1275
1276
1277perl v5.26.3                      2016-07-25               Locale::Maketext(3)
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