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2# This document contains text in Perl "POD" format.
3# Use a POD viewer like perldoc or perlman to render it.
4
5# This corrects some typoes in the previous release.
6
7=head1 NAME
8
9Locale::Maketext::TPJ13 -- article about software localization
10
11=head1 SYNOPSIS
12
13 # This an article, not a module.
14
15=head1 DESCRIPTION
16
17The following article by Sean M. Burke and Jordan Lachler
18first appeared in I<The Perl
19Journal> #13 and is copyright 1999 The Perl Journal. It appears
20courtesy of Jon Orwant and The Perl Journal. This document may be
21distributed under the same terms as Perl itself.
22
23=head1 Localization and Perl: gettext breaks, Maketext fixes
24
25by Sean M. Burke and Jordan Lachler
26
27This article points out cases where gettext (a common system for
28localizing software interfaces -- i.e., making them work in the user's
29language of choice) fails because of basic differences between human
30languages. This article then describes Maketext, a new system capable
31of correctly treating these differences.
32
33=head2 A Localization Horror Story: It Could Happen To You
34
35=over
36
37"There are a number of languages spoken by human beings in this
38world."
39
40-- Harald Tveit Alvestrand, in RFC 1766, "Tags for the
41Identification of Languages"
42
43=back
44
45Imagine that your task for the day is to localize a piece of software
46-- and luckily for you, the only output the program emits is two
47messages, like this:
48
49 I scanned 12 directories.
50
51 Your query matched 10 files in 4 directories.
52
53So how hard could that be? You look at the code that
54produces the first item, and it reads:
55
56 printf("I scanned %g directories.",
57 $directory_count);
58
59You think about that, and realize that it doesn't even work right for
60English, as it can produce this output:
61
62 I scanned 1 directories.
63
64So you rewrite it to read:
65
66 printf("I scanned %g %s.",
67 $directory_count,
68 $directory_count == 1 ?
69 "directory" : "directories",
70 );
71
72...which does the Right Thing. (In case you don't recall, "%g" is for
73locale-specific number interpolation, and "%s" is for string
74interpolation.)
75
76But you still have to localize it for all the languages you're
77producing this software for, so you pull Locale::gettext off of CPAN
78so you can access the C<gettext> C functions you've heard are standard
79for localization tasks.
80
81And you write:
82
83 printf(gettext("I scanned %g %s."),
84 $dir_scan_count,
85 $dir_scan_count == 1 ?
86 gettext("directory") : gettext("directories"),
87 );
88
89But you then read in the gettext manual (Drepper, Miller, and Pinard 1995)
90that this is not a good idea, since how a single word like "directory"
91or "directories" is translated may depend on context -- and this is
92true, since in a case language like German or Russian, you'd may need
93these words with a different case ending in the first instance (where the
94word is the object of a verb) than in the second instance, which you haven't even
95gotten to yet (where the word is the object of a preposition, "in %g
96directories") -- assuming these keep the same syntax when translated
97into those languages.
98
99So, on the advice of the gettext manual, you rewrite:
100
101 printf( $dir_scan_count == 1 ?
102 gettext("I scanned %g directory.") :
103 gettext("I scanned %g directories."),
104 $dir_scan_count );
105
106So, you email your various translators (the boss decides that the
107languages du jour are Chinese, Arabic, Russian, and Italian, so you
108have one translator for each), asking for translations for "I scanned
109%g directory." and "I scanned %g directories.". When they reply,
110you'll put that in the lexicons for gettext to use when it localizes
111your software, so that when the user is running under the "zh"
112(Chinese) locale, gettext("I scanned %g directory.") will return the
113appropriate Chinese text, with a "%g" in there where printf can then
114interpolate $dir_scan.
115
116Your Chinese translator emails right back -- he says both of these
117phrases translate to the same thing in Chinese, because, in linguistic
118jargon, Chinese "doesn't have number as a grammatical category" --
119whereas English does. That is, English has grammatical rules that
120refer to "number", i.e., whether something is grammatically singular
121or plural; and one of these rules is the one that forces nouns to take
122a plural suffix (generally "s") when in a plural context, as they are when
123they follow a number other than "one" (including, oddly enough, "zero").
124Chinese has no such rules, and so has just the one phrase where English
125has two. But, no problem, you can have this one Chinese phrase appear
126as the translation for the two English phrases in the "zh" gettext
127lexicon for your program.
128
129Emboldened by this, you dive into the second phrase that your software
130needs to output: "Your query matched 10 files in 4 directories.". You notice
131that if you want to treat phrases as indivisible, as the gettext
132manual wisely advises, you need four cases now, instead of two, to
133cover the permutations of singular and plural on the two items,
134$dir_count and $file_count. So you try this:
135
136 printf( $file_count == 1 ?
137 ( $directory_count == 1 ?
138 gettext("Your query matched %g file in %g directory.") :
139 gettext("Your query matched %g file in %g directories.") ) :
140 ( $directory_count == 1 ?
141 gettext("Your query matched %g files in %g directory.") :
142 gettext("Your query matched %g files in %g directories.") ),
143 $file_count, $directory_count,
144 );
145
146(The case of "1 file in 2 [or more] directories" could, I suppose,
147occur in the case of symlinking or something of the sort.)
148
149It occurs to you that this is not the prettiest code you've ever
150written, but this seems the way to go. You mail off to the
151translators asking for translations for these four cases. The
152Chinese guy replies with the one phrase that these all translate to in
153Chinese, and that phrase has two "%g"s in it, as it should -- but
154there's a problem. He translates it word-for-word back: "In %g
155directories contains %g files match your query." The %g
156slots are in an order reverse to what they are in English. You wonder
157how you'll get gettext to handle that.
158
159But you put it aside for the moment, and optimistically hope that the
160other translators won't have this problem, and that their languages
161will be better behaved -- i.e., that they will be just like English.
162
163But the Arabic translator is the next to write back. First off, your
164code for "I scanned %g directory." or "I scanned %g directories."
165assumes there's only singular or plural. But, to use linguistic
166jargon again, Arabic has grammatical number, like English (but unlike
167Chinese), but it's a three-term category: singular, dual, and plural.
168In other words, the way you say "directory" depends on whether there's
169one directory, or I<two> of them, or I<more than two> of them. Your
170test of C<($directory == 1)> no longer does the job. And it means
171that where English's grammatical category of number necessitates
172only the two permutations of the first sentence based on "directory
173[singular]" and "directories [plural]", Arabic has three -- and,
174worse, in the second sentence ("Your query matched %g file in %g
175directory."), where English has four, Arabic has nine. You sense
176an unwelcome, exponential trend taking shape.
177
178Your Italian translator emails you back and says that "I searched 0
179directories" (a possible English output of your program) is stilted,
180and if you think that's fine English, that's your problem, but that
181I<just will not do> in the language of Dante. He insists that where
182$directory_count is 0, your program should produce the Italian text
183for "I I<didn't> scan I<any> directories.". And ditto for "I didn't
184match any files in any directories", although he says the last part
185about "in any directories" should probably just be left off.
186
187You wonder how you'll get gettext to handle this; to accomodate the
188ways Arabic, Chinese, and Italian deal with numbers in just these few
189very simple phrases, you need to write code that will ask gettext for
190different queries depending on whether the numerical values in
191question are 1, 2, more than 2, or in some cases 0, and you still haven't
192figured out the problem with the different word order in Chinese.
193
194Then your Russian translator calls on the phone, to I<personally> tell
195you the bad news about how really unpleasant your life is about to
196become:
197
198Russian, like German or Latin, is an inflectional language; that is, nouns
199and adjectives have to take endings that depend on their case
200(i.e., nominative, accusative, genitive, etc...) -- which is roughly a matter of
201what role they have in syntax of the sentence --
202as well as on the grammatical gender (i.e., masculine, feminine, neuter)
203and number (i.e., singular or plural) of the noun, as well as on the
204declension class of the noun. But unlike with most other inflected languages,
205putting a number-phrase (like "ten" or "forty-three", or their Arabic
206numeral equivalents) in front of noun in Russian can change the case and
207number that noun is, and therefore the endings you have to put on it.
208
209He elaborates: In "I scanned %g directories", you'd I<expect>
210"directories" to be in the accusative case (since it is the direct
211object in the sentnce) and the plural number,
212except where $directory_count is 1, then you'd expect the singular, of
213course. Just like Latin or German. I<But!> Where $directory_count %
21410 is 1 ("%" for modulo, remember), assuming $directory count is an
215integer, and except where $directory_count % 100 is 11, "directories"
216is forced to become grammatically singular, which means it gets the
217ending for the accusative singular... You begin to visualize the code
218it'd take to test for the problem so far, I<and still work for Chinese
219and Arabic and Italian>, and how many gettext items that'd take, but
220he keeps going... But where $directory_count % 10 is 2, 3, or 4
221(except where $directory_count % 100 is 12, 13, or 14), the word for
222"directories" is forced to be genitive singular -- which means another
223ending... The room begins to spin around you, slowly at first... But
224with I<all other> integer values, since "directory" is an inanimate
225noun, when preceded by a number and in the nominative or accusative
226cases (as it is here, just your luck!), it does stay plural, but it is
227forced into the genitive case -- yet another ending... And
228you never hear him get to the part about how you're going to run into
229similar (but maybe subtly different) problems with other Slavic
230languages like Polish, because the floor comes up to meet you, and you
231fade into unconsciousness.
232
233
234The above cautionary tale relates how an attempt at localization can
235lead from programmer consternation, to program obfuscation, to a need
236for sedation. But careful evaluation shows that your choice of tools
237merely needed further consideration.
238
239=head2 The Linguistic View
240
241=over
242
243"It is more complicated than you think."
244
245-- The Eighth Networking Truth, from RFC 1925
246
247=back
248
249The field of Linguistics has expended a great deal of effort over the
250past century trying to find grammatical patterns which hold across
251languages; it's been a constant process
252of people making generalizations that should apply to all languages,
253only to find out that, all too often, these generalizations fail --
254sometimes failing for just a few languages, sometimes whole classes of
255languages, and sometimes nearly every language in the world except
256English. Broad statistical trends are evident in what the "average
257language" is like as far as what its rules can look like, must look
258like, and cannot look like. But the "average language" is just as
259unreal a concept as the "average person" -- it runs up against the
260fact no language (or person) is, in fact, average. The wisdom of past
261experience leads us to believe that any given language can do whatever
262it wants, in any order, with appeal to any kind of grammatical
263categories wants -- case, number, tense, real or metaphoric
264characteristics of the things that words refer to, arbitrary or
265predictable classifications of words based on what endings or prefixes
266they can take, degree or means of certainty about the truth of
267statements expressed, and so on, ad infinitum.
268
269Mercifully, most localization tasks are a matter of finding ways to
270translate whole phrases, generally sentences, where the context is
271relatively set, and where the only variation in content is I<usually>
272in a number being expressed -- as in the example sentences above.
273Translating specific, fully-formed sentences is, in practice, fairly
274foolproof -- which is good, because that's what's in the phrasebooks
275that so many tourists rely on. Now, a given phrase (whether in a
276phrasebook or in a gettext lexicon) in one language I<might> have a
277greater or lesser applicability than that phrase's translation into
278another language -- for example, strictly speaking, in Arabic, the
279"your" in "Your query matched..." would take a different form
280depending on whether the user is male or female; so the Arabic
281translation "your[feminine] query" is applicable in fewer cases than
282the corresponding English phrase, which doesn't distinguish the user's
283gender. (In practice, it's not feasable to have a program know the
284user's gender, so the masculine "you" in Arabic is usually used, by
285default.)
286
287But in general, such surprises are rare when entire sentences are
288being translated, especially when the functional context is restricted
289to that of a computer interacting with a user either to convey a fact
290or to prompt for a piece of information. So, for purposes of
291localization, translation by phrase (generally by sentence) is both the
292simplest and the least problematic.
293
294=head2 Breaking gettext
295
296=over
297
298"It Has To Work."
299
300-- First Networking Truth, RFC 1925
301
302=back
303
304Consider that sentences in a tourist phrasebook are of two types: ones
305like "How do I get to the marketplace?" that don't have any blanks to
306fill in, and ones like "How much do these ___ cost?", where there's
307one or more blanks to fill in (and these are usually linked to a
308list of words that you can put in that blank: "fish", "potatoes",
309"tomatoes", etc.) The ones with no blanks are no problem, but the
310fill-in-the-blank ones may not be really straightforward. If it's a
311Swahili phrasebook, for example, the authors probably didn't bother to
312tell you the complicated ways that the verb "cost" changes its
313inflectional prefix depending on the noun you're putting in the blank.
314The trader in the marketplace will still understand what you're saying if
315you say "how much do these potatoes cost?" with the wrong
316inflectional prefix on "cost". After all, I<you> can't speak proper Swahili,
317I<you're> just a tourist. But while tourists can be stupid, computers
318are supposed to be smart; the computer should be able to fill in the
319blank, and still have the results be grammatical.
320
321In other words, a phrasebook entry takes some values as parameters
322(the things that you fill in the blank or blanks), and provides a value
323based on these parameters, where the way you get that final value from
324the given values can, properly speaking, involve an arbitrarily
325complex series of operations. (In the case of Chinese, it'd be not at
326all complex, at least in cases like the examples at the beginning of
327this article; whereas in the case of Russian it'd be a rather complex
328series of operations. And in some languages, the
329complexity could be spread around differently: while the act of
330putting a number-expression in front of a noun phrase might not be
331complex by itself, it may change how you have to, for example, inflect
332a verb elsewhere in the sentence. This is what in syntax is called
333"long-distance dependencies".)
334
335This talk of parameters and arbitrary complexity is just another way
336to say that an entry in a phrasebook is what in a programming language
337would be called a "function". Just so you don't miss it, this is the
338crux of this article: I<A phrase is a function; a phrasebook is a
339bunch of functions.>
340
341The reason that using gettext runs into walls (as in the above
342second-person horror story) is that you're trying to use a string (or
343worse, a choice among a bunch of strings) to do what you really need a
344function for -- which is futile. Preforming (s)printf interpolation
345on the strings which you get back from gettext does allow you to do I<some>
346common things passably well... sometimes... sort of; but, to paraphrase
347what some people say about C<csh> script programming, "it fools you
348into thinking you can use it for real things, but you can't, and you
349don't discover this until you've already spent too much time trying,
350and by then it's too late."
351
352=head2 Replacing gettext
353
354So, what needs to replace gettext is a system that supports lexicons
355of functions instead of lexicons of strings. An entry in a lexicon
356from such a system should I<not> look like this:
357
358 "J'ai trouv\xE9 %g fichiers dans %g r\xE9pertoires"
359
360[\xE9 is e-acute in Latin-1. Some pod renderers would
361scream if I used the actual character here. -- SB]
362
363but instead like this, bearing in mind that this is just a first stab:
364
365 sub I_found_X1_files_in_X2_directories {
366 my( $files, $dirs ) = @_[0,1];
367 $files = sprintf("%g %s", $files,
368 $files == 1 ? 'fichier' : 'fichiers');
369 $dirs = sprintf("%g %s", $dirs,
370 $dirs == 1 ? "r\xE9pertoire" : "r\xE9pertoires");
371 return "J'ai trouv\xE9 $files dans $dirs.";
372 }
373
374Now, there's no particularly obvious way to store anything but strings
375in a gettext lexicon; so it looks like we just have to start over and
376make something better, from scratch. I call my shot at a
377gettext-replacement system "Maketext", or, in CPAN terms,
378Locale::Maketext.
379
380When designing Maketext, I chose to plan its main features in terms of
381"buzzword compliance". And here are the buzzwords:
382
383=head2 Buzzwords: Abstraction and Encapsulation
384
385The complexity of the language you're trying to output a phrase in is
386entirely abstracted inside (and encapsulated within) the Maketext module
387for that interface. When you call:
388
389 print $lang->maketext("You have [quant,_1,piece] of new mail.",
390 scalar(@messages));
391
392you don't know (and in fact can't easily find out) whether this will
393involve lots of figuring, as in Russian (if $lang is a handle to the
394Russian module), or relatively little, as in Chinese. That kind of
395abstraction and encapsulation may encourage other pleasant buzzwords
396like modularization and stratification, depending on what design
397decisions you make.
398
399=head2 Buzzword: Isomorphism
400
401"Isomorphism" means "having the same structure or form"; in discussions
402of program design, the word takes on the special, specific meaning that
403your implementation of a solution to a problem I<has the same
404structure> as, say, an informal verbal description of the solution, or
405maybe of the problem itself. Isomorphism is, all things considered,
406a good thing -- it's what problem-solving (and solution-implementing)
407should look like.
408
409What's wrong the with gettext-using code like this...
410
411 printf( $file_count == 1 ?
412 ( $directory_count == 1 ?
413 "Your query matched %g file in %g directory." :
414 "Your query matched %g file in %g directories." ) :
415 ( $directory_count == 1 ?
416 "Your query matched %g files in %g directory." :
417 "Your query matched %g files in %g directories." ),
418 $file_count, $directory_count,
419 );
420
421is first off that it's not well abstracted -- these ways of testing
422for grammatical number (as in the expressions like C<foo == 1 ?
423singular_form : plural_form>) should be abstracted to each language
424module, since how you get grammatical number is language-specific.
425
426But second off, it's not isomorphic -- the "solution" (i.e., the
427phrasebook entries) for Chinese maps from these four English phrases to
428the one Chinese phrase that fits for all of them. In other words, the
429informal solution would be "The way to say what you want in Chinese is
430with the one phrase 'For your question, in Y directories you would
431find X files'" -- and so the implemented solution should be,
432isomorphically, just a straightforward way to spit out that one
433phrase, with numerals properly interpolated. It shouldn't have to map
434from the complexity of other languages to the simplicity of this one.
435
436=head2 Buzzword: Inheritance
437
438There's a great deal of reuse possible for sharing of phrases between
439modules for related dialects, or for sharing of auxiliary functions
440between related languages. (By "auxiliary functions", I mean
441functions that don't produce phrase-text, but which, say, return an
442answer to "does this number require a plural noun after it?". Such
443auxiliary functions would be used in the internal logic of functions
444that actually do produce phrase-text.)
445
446In the case of sharing phrases, consider that you have an interface
447already localized for American English (probably by having been
448written with that as the native locale, but that's incidental).
449Localizing it for UK English should, in practical terms, be just a
450matter of running it past a British person with the instructions to
451indicate what few phrases would benefit from a change in spelling or
452possibly minor rewording. In that case, you should be able to put in
453the UK English localization module I<only> those phrases that are
454UK-specific, and for all the rest, I<inherit> from the American
455English module. (And I expect this same situation would apply with
456Brazilian and Continental Portugese, possbily with some I<very>
457closely related languages like Czech and Slovak, and possibly with the
458slightly different "versions" of written Mandarin Chinese, as I hear exist in
459Taiwan and mainland China.)
460
461As to sharing of auxiliary functions, consider the problem of Russian
462numbers from the beginning of this article; obviously, you'd want to
463write only once the hairy code that, given a numeric value, would
464return some specification of which case and number a given quanitified
465noun should use. But suppose that you discover, while localizing an
466interface for, say, Ukranian (a Slavic language related to Russian,
467spoken by several million people, many of whom would be relieved to
468find that your Web site's or software's interface is available in
469their language), that the rules in Ukranian are the same as in Russian
470for quantification, and probably for many other grammatical functions.
471While there may well be no phrases in common between Russian and
472Ukranian, you could still choose to have the Ukranian module inherit
473from the Russian module, just for the sake of inheriting all the
474various grammatical methods. Or, probably better organizationally,
475you could move those functions to a module called C<_E_Slavic> or
476something, which Russian and Ukranian could inherit useful functions
477from, but which would (presumably) provide no lexicon.
478
479=head2 Buzzword: Concision
480
481Okay, concision isn't a buzzword. But it should be, so I decree that
482as a new buzzword, "concision" means that simple common things should
483be expressible in very few lines (or maybe even just a few characters)
484of code -- call it a special case of "making simple things easy and
485hard things possible", and see also the role it played in the
486MIDI::Simple language, discussed elsewhere in this issue [TPJ#13].
487
488Consider our first stab at an entry in our "phrasebook of functions":
489
490 sub I_found_X1_files_in_X2_directories {
491 my( $files, $dirs ) = @_[0,1];
492 $files = sprintf("%g %s", $files,
493 $files == 1 ? 'fichier' : 'fichiers');
494 $dirs = sprintf("%g %s", $dirs,
495 $dirs == 1 ? "r\xE9pertoire" : "r\xE9pertoires");
496 return "J'ai trouv\xE9 $files dans $dirs.";
497 }
498
499You may sense that a lexicon (to use a non-committal catch-all term for a
500collection of things you know how to say, regardless of whether they're
501phrases or words) consisting of functions I<expressed> as above would
502make for rather long-winded and repetitive code -- even if you wisely
503rewrote this to have quantification (as we call adding a number
504expression to a noun phrase) be a function called like:
505
506 sub I_found_X1_files_in_X2_directories {
507 my( $files, $dirs ) = @_[0,1];
508 $files = quant($files, "fichier");
509 $dirs = quant($dirs, "r\xE9pertoire");
510 return "J'ai trouv\xE9 $files dans $dirs.";
511 }
512
513And you may also sense that you do not want to bother your translators
514with having to write Perl code -- you'd much rather that they spend
515their I<very costly time> on just translation. And this is to say
516nothing of the near impossibility of finding a commercial translator
517who would know even simple Perl.
518
519In a first-hack implementation of Maketext, each language-module's
520lexicon looked like this:
521
522 %Lexicon = (
523 "I found %g files in %g directories"
524 => sub {
525 my( $files, $dirs ) = @_[0,1];
526 $files = quant($files, "fichier");
527 $dirs = quant($dirs, "r\xE9pertoire");
528 return "J'ai trouv\xE9 $files dans $dirs.";
529 },
530 ... and so on with other phrase => sub mappings ...
531 );
532
533but I immediately went looking for some more concise way to basically
534denote the same phrase-function -- a way that would also serve to
535concisely denote I<most> phrase-functions in the lexicon for I<most>
536languages. After much time and even some actual thought, I decided on
537this system:
538
539* Where a value in a %Lexicon hash is a contentful string instead of
540an anonymous sub (or, conceivably, a coderef), it would be interpreted
541as a sort of shorthand expression of what the sub does. When accessed
542for the first time in a session, it is parsed, turned into Perl code,
543and then eval'd into an anonymous sub; then that sub replaces the
544original string in that lexicon. (That way, the work of parsing and
545evaling the shorthand form for a given phrase is done no more than
546once per session.)
547
548* Calls to C<maketext> (as Maketext's main function is called) happen
549thru a "language session handle", notionally very much like an IO
550handle, in that you open one at the start of the session, and use it
551for "sending signals" to an object in order to have it return the text
552you want.
553
554So, this:
555
556 $lang->maketext("You have [quant,_1,piece] of new mail.",
557 scalar(@messages));
558
559basically means this: look in the lexicon for $lang (which may inherit
560from any number of other lexicons), and find the function that we
561happen to associate with the string "You have [quant,_1,piece] of new
562mail" (which is, and should be, a functioning "shorthand" for this
563function in the native locale -- English in this case). If you find
564such a function, call it with $lang as its first parameter (as if it
565were a method), and then a copy of scalar(@messages) as its second,
566and then return that value. If that function was found, but was in
567string shorthand instead of being a fully specified function, parse it
568and make it into a function before calling it the first time.
569
570* The shorthand uses code in brackets to indicate method calls that
571should be performed. A full explanation is not in order here, but a
572few examples will suffice:
573
574 "You have [quant,_1,piece] of new mail."
575
576The above code is shorthand for, and will be interpreted as,
577this:
578
579 sub {
580 my $handle = $_[0];
581 my(@params) = @_;
582 return join '',
583 "You have ",
584 $handle->quant($params[1], 'piece'),
585 "of new mail.";
586 }
587
588where "quant" is the name of a method you're using to quantify the
589noun "piece" with the number $params[0].
590
591A string with no brackety calls, like this:
592
593 "Your search expression was malformed."
594
595is somewhat of a degerate case, and just gets turned into:
596
597 sub { return "Your search expression was malformed." }
598
599However, not everything you can write in Perl code can be written in
600the above shorthand system -- not by a long shot. For example, consider
601the Italian translator from the beginning of this article, who wanted
602the Italian for "I didn't find any files" as a special case, instead
603of "I found 0 files". That couldn't be specified (at least not easily
604or simply) in our shorthand system, and it would have to be written
605out in full, like this:
606
607 sub { # pretend the English strings are in Italian
608 my($handle, $files, $dirs) = @_[0,1,2];
609 return "I didn't find any files" unless $files;
610 return join '',
611 "I found ",
612 $handle->quant($files, 'file'),
613 " in ",
614 $handle->quant($dirs, 'directory'),
615 ".";
616 }
617
618Next to a lexicon full of shorthand code, that sort of sticks out like a
619sore thumb -- but this I<is> a special case, after all; and at least
620it's possible, if not as concise as usual.
621
622As to how you'd implement the Russian example from the beginning of
623the article, well, There's More Than One Way To Do It, but it could be
624something like this (using English words for Russian, just so you know
625what's going on):
626
627 "I [quant,_1,directory,accusative] scanned."
628
629This shifts the burden of complexity off to the quant method. That
630method's parameters are: the numeric value it's going to use to
631quantify something; the Russian word it's going to quantify; and the
632parameter "accusative", which you're using to mean that this
633sentence's syntax wants a noun in the accusative case there, although
634that quantification method may have to overrule, for grammatical
635reasons you may recall from the beginning of this article.
636
637Now, the Russian quant method here is responsible not only for
638implementing the strange logic necessary for figuring out how Russian
639number-phrases impose case and number on their noun-phrases, but also
640for inflecting the Russian word for "directory". How that inflection
641is to be carried out is no small issue, and among the solutions I've
642seen, some (like variations on a simple lookup in a hash where all
643possible forms are provided for all necessary words) are
644straightforward but I<can> become cumbersome when you need to inflect
645more than a few dozen words; and other solutions (like using
646algorithms to model the inflections, storing only root forms and
647irregularities) I<can> involve more overhead than is justifiable for
648all but the largest lexicons.
649
650Mercifully, this design decision becomes crucial only in the hairiest
651of inflected languages, of which Russian is by no means the I<worst> case
652scenario, but is worse than most. Most languages have simpler
653inflection systems; for example, in English or Swahili, there are
654generally no more than two possible inflected forms for a given noun
655("error/errors"; "kosa/makosa"), and the
656rules for producing these forms are fairly simple -- or at least,
657simple rules can be formulated that work for most words, and you can
658then treat the exceptions as just "irregular", at least relative to
659your ad hoc rules. A simpler inflection system (simpler rules, fewer
660forms) means that design decisions are less crucial to maintaining
661sanity, whereas the same decisions could incur
662overhead-versus-scalability problems in languages like Russian. It
663may I<also> be likely that code (possibly in Perl, as with
664Lingua::EN::Inflect, for English nouns) has already
665been written for the language in question, whether simple or complex.
666
667Moreover, a third possibility may even be simpler than anything
668discussed above: "Just require that all possible (or at least
669applicable) forms be provided in the call to the given language's quant
670method, as in:"
671
672 "I found [quant,_1,file,files]."
673
674That way, quant just has to chose which form it needs, without having
675to look up or generate anything. While possibly not optimal for
676Russian, this should work well for most other languages, where
677quantification is not as complicated an operation.
678
679=head2 The Devil in the Details
680
681There's plenty more to Maketext than described above -- for example,
682there's the details of how language tags ("en-US", "i-pwn", "fi",
683etc.) or locale IDs ("en_US") interact with actual module naming
684("BogoQuery/Locale/en_us.pm"), and what magic can ensue; there's the
685details of how to record (and possibly negotiate) what character
686encoding Maketext will return text in (UTF8? Latin-1? KOI8?). There's
687the interesting fact that Maketext is for localization, but nowhere
688actually has a "C<use locale;>" anywhere in it. For the curious,
689there's the somewhat frightening details of how I actually
690implement something like data inheritance so that searches across
691modules' %Lexicon hashes can parallel how Perl implements method
692inheritance.
693
694And, most importantly, there's all the practical details of how to
695actually go about deriving from Maketext so you can use it for your
696interfaces, and the various tools and conventions for starting out and
697maintaining individual language modules.
698
699That is all covered in the documentation for Locale::Maketext and the
700modules that come with it, available in CPAN. After having read this
701article, which covers the why's of Maketext, the documentation,
702which covers the how's of it, should be quite straightfoward.
703
704=head2 The Proof in the Pudding: Localizing Web Sites
705
706Maketext and gettext have a notable difference: gettext is in C,
707accessible thru C library calls, whereas Maketext is in Perl, and
708really can't work without a Perl interpreter (although I suppose
709something like it could be written for C). Accidents of history (and
710not necessarily lucky ones) have made C++ the most common language for
711the implementation of applications like word processors, Web browsers,
712and even many in-house applications like custom query systems. Current
713conditions make it somewhat unlikely that the next one of any of these
714kinds of applications will be written in Perl, albeit clearly more for
715reasons of custom and inertia than out of consideration of what is the
716right tool for the job.
717
718However, other accidents of history have made Perl a well-accepted
719language for design of server-side programs (generally in CGI form)
720for Web site interfaces. Localization of static pages in Web sites is
721trivial, feasable either with simple language-negotiation features in
722servers like Apache, or with some kind of server-side inclusions of
723language-appropriate text into layout templates. However, I think
724that the localization of Perl-based search systems (or other kinds of
725dynamic content) in Web sites, be they public or access-restricted,
726is where Maketext will see the greatest use.
727
728I presume that it would be only the exceptional Web site that gets
729localized for English I<and> Chinese I<and> Italian I<and> Arabic
730I<and> Russian, to recall the languages from the beginning of this
731article -- to say nothing of German, Spanish, French, Japanese,
732Finnish, and Hindi, to name a few languages that benefit from large
733numbers of programmers or Web viewers or both.
734
735However, the ever-increasing internationalization of the Web (whether
736measured in terms of amount of content, of numbers of content writers
737or programmers, or of size of content audiences) makes it increasingly
738likely that the interface to the average Web-based dynamic content
739service will be localized for two or maybe three languages. It is my
740hope that Maketext will make that task as simple as possible, and will
741remove previous barriers to localization for languages dissimilar to
742English.
743
744 __END__
745
746Sean M. Burke (sburkeE<64>cpan.org) has a Master's in linguistics
747from Northwestern University; he specializes in language technology.
748Jordan Lachler (lachlerE<64>unm.edu) is a PhD student in the Department of
749Linguistics at the University of New Mexico; he specializes in
750morphology and pedagogy of North American native languages.
751
752=head2 References
753
754Alvestrand, Harald Tveit. 1995. I<RFC 1766: Tags for the
755Identification of Languages.>
756C<ftp://ftp.isi.edu/in-notes/rfc1766.txt>
757[Now see RFC 3066.]
758
759Callon, Ross, editor. 1996. I<RFC 1925: The Twelve
760Networking Truths.>
761C<ftp://ftp.isi.edu/in-notes/rfc1925.txt>
762
763Drepper, Ulrich, Peter Miller,
764and FranE<ccedil>ois Pinard. 1995-2001. GNU
765C<gettext>. Available in C<ftp://prep.ai.mit.edu/pub/gnu/>, with
766extensive docs in the distribution tarball. [Since
767I wrote this article in 1998, I now see that the
768gettext docs are now trying more to come to terms with
769plurality. Whether useful conclusions have come from it
770is another question altogether. -- SMB, May 2001]
771
772Forbes, Nevill. 1964. I<Russian Grammar.> Third Edition, revised
773by J. C. Dumbreck. Oxford University Press.
774
775=cut
776
777#End
778
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