version 1 showing authors affecting page license.
.
Rev |
Author |
# |
Line |
1 |
perry |
1 |
PERLLOCALE |
|
|
2 |
!!!PERLLOCALE |
|
|
3 |
NAME |
|
|
4 |
DESCRIPTION |
|
|
5 |
PREPARING TO USE LOCALES |
|
|
6 |
USING LOCALES |
|
|
7 |
LOCALE CATEGORIES |
|
|
8 |
SECURITY |
|
|
9 |
ENVIRONMENT |
|
|
10 |
NOTES |
|
|
11 |
BUGS |
|
|
12 |
SEE ALSO |
|
|
13 |
HISTORY |
|
|
14 |
---- |
|
|
15 |
!!NAME |
|
|
16 |
|
|
|
17 |
|
|
|
18 |
perllocale - Perl locale handling (internationalization and localization) |
|
|
19 |
!!DESCRIPTION |
|
|
20 |
|
|
|
21 |
|
|
|
22 |
Perl supports language-specific notions of data such as ``is |
|
|
23 |
this a letter'', ``what is the uppercase equivalent of this |
|
|
24 |
letter'', and ``which of these letters comes first''. These |
|
|
25 |
are important issues, especially for languages other than |
|
|
26 |
English--but also for English: it would be naieve to imagine |
|
|
27 |
that A-Za-z defines all the ``letters'' needed to |
|
|
28 |
write in English. Perl is also aware that some character |
|
|
29 |
other than '.' may be preferred as a decimal point, and that |
|
|
30 |
output date representations may be language-specific. The |
|
|
31 |
process of making an application take account of its users' |
|
|
32 |
preferences in such matters is called |
|
|
33 |
__internationalization__ (often abbreviated as |
|
|
34 |
__i18n__); telling such an application about a particular |
|
|
35 |
set of preferences is known as __localization__ |
|
|
36 |
(__l10n__). |
|
|
37 |
|
|
|
38 |
|
|
|
39 |
Perl can understand language-specific data via the |
|
|
40 |
standardized ( ISO C, XPG4 , |
|
|
41 |
POSIX 1.c) method called ``the locale |
|
|
42 |
system''. The locale system is controlled per application |
|
|
43 |
using one pragma, one function call, and several environment |
|
|
44 |
variables. |
|
|
45 |
|
|
|
46 |
|
|
|
47 |
__NOTE__ : This feature is new in Perl |
|
|
48 |
5.004, and does not apply unless an application specifically |
|
|
49 |
requests it--see ``Backward compatibility''. The one |
|
|
50 |
exception is that ''write()'' now __always__ uses the |
|
|
51 |
current locale - see `` NOTES |
|
|
52 |
''. |
|
|
53 |
!!PREPARING TO USE LOCALES |
|
|
54 |
|
|
|
55 |
|
|
|
56 |
If Perl applications are to understand and present your data |
|
|
57 |
correctly according a locale of your choice, __all__ of |
|
|
58 |
the following must be true: |
|
|
59 |
|
|
|
60 |
|
|
|
61 |
__Your operating system must support the locale system__. |
|
|
62 |
If it does, you should find that the ''setlocale()'' |
|
|
63 |
function is a documented part of its C library. |
|
|
64 |
|
|
|
65 |
|
|
|
66 |
__Definitions for locales that you use must be |
|
|
67 |
installed__. You, or your system administrator, must make |
|
|
68 |
sure that this is the case. The available locales, the |
|
|
69 |
location in which they are kept, and the manner in which |
|
|
70 |
they are installed all vary from system to system. Some |
|
|
71 |
systems provide only a few, hard-wired locales and do not |
|
|
72 |
allow more to be added. Others allow you to add ``canned'' |
|
|
73 |
locales provided by the system supplier. Still others allow |
|
|
74 |
you or the system administrator to define and add arbitrary |
|
|
75 |
locales. (You may have to ask your supplier to provide |
|
|
76 |
canned locales that are not delivered with your operating |
|
|
77 |
system.) Read your system documentation for further |
|
|
78 |
illumination. |
|
|
79 |
|
|
|
80 |
|
|
|
81 |
__Perl must believe that the locale system is |
|
|
82 |
supported__. If it does, perl -V:d_setlocale will |
|
|
83 |
say that the value for d_setlocale is |
|
|
84 |
define. |
|
|
85 |
|
|
|
86 |
|
|
|
87 |
If you want a Perl application to process and present your |
|
|
88 |
data according to a particular locale, the application code |
|
|
89 |
should include the use locale pragma (see ``The use |
|
|
90 |
locale pragma'') where appropriate, and __at least one__ |
|
|
91 |
of the following must be true: |
|
|
92 |
|
|
|
93 |
|
|
|
94 |
__The locale-determining environment variables (see `` |
|
|
95 |
ENVIRONMENT '') must be correctly set up__ |
|
|
96 |
at the time the application is started, either by yourself |
|
|
97 |
or by whoever set up your system account. |
|
|
98 |
|
|
|
99 |
|
|
|
100 |
__The application must set its own locale__ using the |
|
|
101 |
method described in ``The setlocale function''. |
|
|
102 |
!!USING LOCALES |
|
|
103 |
|
|
|
104 |
|
|
|
105 |
__The use locale pragma__ |
|
|
106 |
|
|
|
107 |
|
|
|
108 |
By default, Perl ignores the current locale. The use |
|
|
109 |
locale pragma tells Perl to use the current locale for |
|
|
110 |
some operations: |
|
|
111 |
|
|
|
112 |
|
|
|
113 |
__The comparison operators__ (lt, le, |
|
|
114 |
cmp, ge, and gt) and the |
|
|
115 |
POSIX string collation functions |
|
|
116 |
''strcoll()'' and ''strxfrm()'' use |
|
|
117 |
LC_COLLATE. ''sort()'' is also affected if used |
|
|
118 |
without an explicit comparison function, because it uses |
|
|
119 |
cmp by default. |
|
|
120 |
|
|
|
121 |
|
|
|
122 |
__Note:__ eq and ne are unaffected by |
|
|
123 |
locale: they always perform a byte-by-byte comparison of |
|
|
124 |
their scalar operands. What's more, if cmp finds |
|
|
125 |
that its operands are equal according to the collation |
|
|
126 |
sequence specified by the current locale, it goes on to |
|
|
127 |
perform a byte-by-byte comparison, and only returns ''0'' |
|
|
128 |
(equal) if the operands are bit-for-bit identical. If you |
|
|
129 |
really want to know whether two strings--which eq |
|
|
130 |
and cmp may consider different--are equal as far as |
|
|
131 |
collation in the locale is concerned, see the discussion in |
|
|
132 |
``Category LC_COLLATE: |
|
|
133 |
Collation''. |
|
|
134 |
|
|
|
135 |
|
|
|
136 |
__Regular expressions and case-modification functions__ |
|
|
137 |
(''uc()'', ''lc()'', ''ucfirst()'', and |
|
|
138 |
''lcfirst()'') use LC_CTYPE |
|
|
139 |
|
|
|
140 |
|
|
|
141 |
__The formatting functions__ (''printf()'', |
|
|
142 |
''sprintf()'' and ''write()'') use |
|
|
143 |
LC_NUMERIC |
|
|
144 |
|
|
|
145 |
|
|
|
146 |
__The POSIX date formatting function__ |
|
|
147 |
(''strftime()'') uses LC_TIME. |
|
|
148 |
|
|
|
149 |
|
|
|
150 |
LC_COLLATE, LC_CTYPE, and so on, are |
|
|
151 |
discussed further in `` LOCALE CATEGORIES |
|
|
152 |
''. |
|
|
153 |
|
|
|
154 |
|
|
|
155 |
The default behavior is restored with the no locale |
|
|
156 |
pragma, or upon reaching the end of block enclosing use |
|
|
157 |
locale. |
|
|
158 |
|
|
|
159 |
|
|
|
160 |
The string result of any operation that uses locale |
|
|
161 |
information is tainted, as it is possible for a locale to be |
|
|
162 |
untrustworthy. See `` SECURITY |
|
|
163 |
''. |
|
|
164 |
|
|
|
165 |
|
|
|
166 |
__The setlocale function__ |
|
|
167 |
|
|
|
168 |
|
|
|
169 |
You can switch locales as often as you wish at run time with |
|
|
170 |
the ''POSIX::setlocale()'' function: |
|
|
171 |
|
|
|
172 |
|
|
|
173 |
# This functionality not usable prior to Perl 5.004 |
|
|
174 |
require 5.004; |
|
|
175 |
# Import locale-handling tool set from POSIX module. |
|
|
176 |
# This example uses: setlocale -- the function call |
|
|
177 |
# LC_CTYPE -- explained below |
|
|
178 |
use POSIX qw(locale_h); |
|
|
179 |
# query and save the old locale |
|
|
180 |
$old_locale = setlocale(LC_CTYPE); |
|
|
181 |
setlocale(LC_CTYPE, |
|
|
182 |
setlocale(LC_CTYPE, |
|
|
183 |
# restore the old locale |
|
|
184 |
setlocale(LC_CTYPE, $old_locale); |
|
|
185 |
The first argument of ''setlocale()'' gives the __category__, the second the __locale__. The category tells in what aspect of data processing you want to apply locale-specific rules. Category names are discussed in `` LOCALE CATEGORIES '' and `` ENVIRONMENT ''. The locale is the name of a collection of customization information corresponding to a particular combination of language, country or territory, and codeset. Read on for hints on the naming of locales: not all systems name locales as in the example. |
|
|
186 |
|
|
|
187 |
|
|
|
188 |
If no second argument is provided and the category is |
|
|
189 |
something else than LC_ALL , the function |
|
|
190 |
returns a string naming the current locale for the category. |
|
|
191 |
You can use this value as the second argument in a |
|
|
192 |
subsequent call to ''setlocale()''. |
|
|
193 |
|
|
|
194 |
|
|
|
195 |
If no second argument is provided and the category is |
|
|
196 |
LC_ALL , the result is |
|
|
197 |
implementation-dependent. It may be a string of concatenated |
|
|
198 |
locales names (separator also implementation-dependent) or a |
|
|
199 |
single locale name. Please consult your setlocale(3) |
|
|
200 |
for details. |
|
|
201 |
|
|
|
202 |
|
|
|
203 |
If a second argument is given and it corresponds to a valid |
|
|
204 |
locale, the locale for the category is set to that value, |
|
|
205 |
and the function returns the now-current locale value. You |
|
|
206 |
can then use this in yet another call to ''setlocale()''. |
|
|
207 |
(In some implementations, the return value may sometimes |
|
|
208 |
differ from the value you gave as the second argument--think |
|
|
209 |
of it as an alias for the value you gave.) |
|
|
210 |
|
|
|
211 |
|
|
|
212 |
As the example shows, if the second argument is an empty |
|
|
213 |
string, the category's locale is returned to the default |
|
|
214 |
specified by the corresponding environment variables. |
|
|
215 |
Generally, this results in a return to the default that was |
|
|
216 |
in force when Perl started up: changes to the environment |
|
|
217 |
made by the application after startup may or may not be |
|
|
218 |
noticed, depending on your system's C library. |
|
|
219 |
|
|
|
220 |
|
|
|
221 |
If the second argument does not correspond to a valid |
|
|
222 |
locale, the locale for the category is not changed, and the |
|
|
223 |
function returns ''undef''. |
|
|
224 |
|
|
|
225 |
|
|
|
226 |
For further information about the categories, consult |
|
|
227 |
setlocale(3). |
|
|
228 |
|
|
|
229 |
|
|
|
230 |
__Finding locales__ |
|
|
231 |
|
|
|
232 |
|
|
|
233 |
For locales available in your system, consult also |
|
|
234 |
setlocale(3) to see whether it leads to the list of |
|
|
235 |
available locales (search for the ''SEE |
|
|
236 |
ALSO'' section). If that fails, try the following |
|
|
237 |
command lines: |
|
|
238 |
|
|
|
239 |
|
|
|
240 |
locale -a |
|
|
241 |
nlsinfo |
|
|
242 |
ls /usr/lib/nls/loc |
|
|
243 |
ls /usr/lib/locale |
|
|
244 |
ls /usr/lib/nls |
|
|
245 |
ls /usr/share/locale |
|
|
246 |
and see whether they list something resembling these |
|
|
247 |
|
|
|
248 |
|
|
|
249 |
en_US.ISO8859-1 de_DE.ISO8859-1 ru_RU.ISO8859-5 |
|
|
250 |
en_US.iso88591 de_DE.iso88591 ru_RU.iso88595 |
|
|
251 |
en_US de_DE ru_RU |
|
|
252 |
en de ru |
|
|
253 |
english german russian |
|
|
254 |
english.iso88591 german.iso88591 russian.iso88595 |
|
|
255 |
english.roman8 russian.koi8r |
|
|
256 |
Sadly, even though the calling interface for ''setlocale()'' has been standardized, names of locales and the directories where the configuration resides have not been. The basic form of the name is ''language_territory''__.__''codeset'', but the latter parts after ''language'' are not always present. The ''language'' and ''country'' are usually from the standards __ISO 3166__ and __ISO 639__, the two-letter abbreviations for the countries and the languages of the world, respectively. The ''codeset'' part often mentions some __ISO 8859__ character set, the Latin codesets. For example, ISO 8859-1 is the so-called ``Western European codeset'' that can be used to encode most Western European languages adequately. Again, there are several ways to write even the name of that one standard. Lamentably. |
|
|
257 |
|
|
|
258 |
|
|
|
259 |
Two special locales are worth particular mention: ``C'' and |
|
|
260 |
`` POSIX ''. Currently these are effectively |
|
|
261 |
the same locale: the difference is mainly that the first one |
|
|
262 |
is defined by the C standard, the second by the |
|
|
263 |
POSIX standard. They define the __default |
|
|
264 |
locale__ in which every program starts in the absence of |
|
|
265 |
locale information in its environment. (The ''default'' |
|
|
266 |
default locale, if you will.) Its language is (American) |
|
|
267 |
English and its character codeset ASCII |
|
|
268 |
. |
|
|
269 |
|
|
|
270 |
|
|
|
271 |
__NOTE__ : Not all systems have the `` |
|
|
272 |
POSIX '' locale (not all systems are |
|
|
273 |
POSIX-conformant), so use ``C'' when you need explicitly to |
|
|
274 |
specify this default locale. |
|
|
275 |
|
|
|
276 |
|
|
|
277 |
__LOCALE PROBLEMS__ |
|
|
278 |
|
|
|
279 |
|
|
|
280 |
You may encounter the following warning message at Perl |
|
|
281 |
startup: |
|
|
282 |
|
|
|
283 |
|
|
|
284 |
perl: warning: Setting locale failed. |
|
|
285 |
perl: warning: Please check that your locale settings: |
|
|
286 |
LC_ALL = |
|
|
287 |
This means that your locale settings had LC_ALL set to ``En_US'' and LANG exists but has no value. Perl tried to believe you but could not. Instead, Perl gave up and fell back to the ``C'' locale, the default locale that is supposed to work no matter what. This usually means your locale settings were wrong, they mention locales your system has never heard of, or the locale installation in your system has problems (for example, some system files are broken or missing). There are quick and temporary fixes to these problems, as well as more thorough and lasting fixes. |
|
|
288 |
|
|
|
289 |
|
|
|
290 |
__Temporarily fixing locale problems__ |
|
|
291 |
|
|
|
292 |
|
|
|
293 |
The two quickest fixes are either to render Perl silent |
|
|
294 |
about any locale inconsistencies or to run Perl under the |
|
|
295 |
default locale ``C''. |
|
|
296 |
|
|
|
297 |
|
|
|
298 |
Perl's moaning about locale problems can be silenced by |
|
|
299 |
setting the environment variable PERL_BADLANG |
|
|
300 |
to a zero value, for example ``0''. This method really just |
|
|
301 |
sweeps the problem under the carpet: you tell Perl to shut |
|
|
302 |
up even when Perl sees that something is wrong. Do not be |
|
|
303 |
surprised if later something locale-dependent |
|
|
304 |
misbehaves. |
|
|
305 |
|
|
|
306 |
|
|
|
307 |
Perl can be run under the ``C'' locale by setting the |
|
|
308 |
environment variable LC_ALL to ``C''. This |
|
|
309 |
method is perhaps a bit more civilized than the |
|
|
310 |
PERL_BADLANG approach, but setting |
|
|
311 |
LC_ALL (or other locale variables) may affect |
|
|
312 |
other programs as well, not just Perl. In particular, |
|
|
313 |
external programs run from within Perl will see these |
|
|
314 |
changes. If you make the new settings permanent (read on), |
|
|
315 |
all programs you run see the changes. See |
|
|
316 |
ENVIRONMENT for the full list of relevant |
|
|
317 |
environment variables and `` USING LOCALES '' |
|
|
318 |
for their effects in Perl. Effects in other programs are |
|
|
319 |
easily deducible. For example, the variable |
|
|
320 |
LC_COLLATE may well affect your __sort__ |
|
|
321 |
program (or whatever the program that arranges `records' |
|
|
322 |
alphabetically in your system is called). |
|
|
323 |
|
|
|
324 |
|
|
|
325 |
You can test out changing these variables temporarily, and |
|
|
326 |
if the new settings seem to help, put those settings into |
|
|
327 |
your shell startup files. Consult your local documentation |
|
|
328 |
for the exact details. For in Bourne-like shells (__sh__, |
|
|
329 |
__ksh__, __bash__, __zsh__): |
|
|
330 |
|
|
|
331 |
|
|
|
332 |
LC_ALL=en_US.ISO8859-1 |
|
|
333 |
export LC_ALL |
|
|
334 |
This assumes that we saw the locale ``en_US.ISO8859-1'' using the commands discussed above. We decided to try that instead of the above faulty locale ``En_US''--and in Cshish shells (__csh__, __tcsh__) |
|
|
335 |
|
|
|
336 |
|
|
|
337 |
setenv LC_ALL en_US.ISO8859-1 |
|
|
338 |
If you do not know what shell you have, consult your local helpdesk or the equivalent. |
|
|
339 |
|
|
|
340 |
|
|
|
341 |
__Permanently fixing locale problems__ |
|
|
342 |
|
|
|
343 |
|
|
|
344 |
The slower but superior fixes are when you may be able to |
|
|
345 |
yourself fix the misconfiguration of your own environment |
|
|
346 |
variables. The mis(sing)configuration of the whole system's |
|
|
347 |
locales usually requires the help of your friendly system |
|
|
348 |
administrator. |
|
|
349 |
|
|
|
350 |
|
|
|
351 |
First, see earlier in this document about ``Finding |
|
|
352 |
locales''. That tells how to find which locales are really |
|
|
353 |
supported--and more importantly, installed--on your system. |
|
|
354 |
In our example error message, environment variables |
|
|
355 |
affecting the locale are listed in the order of decreasing |
|
|
356 |
importance (and unset variables do not matter). Therefore, |
|
|
357 |
having LC_ALL set to ``En_US'' must have been |
|
|
358 |
the bad choice, as shown by the error message. First try |
|
|
359 |
fixing locale settings listed first. |
|
|
360 |
|
|
|
361 |
|
|
|
362 |
Second, if using the listed commands you see something |
|
|
363 |
__exactly__ (prefix matches do not count and case usually |
|
|
364 |
counts) like ``En_US'' without the quotes, then you should |
|
|
365 |
be okay because you are using a locale name that should be |
|
|
366 |
installed and available in your system. In this case, see |
|
|
367 |
``Permanently fixing your system's locale |
|
|
368 |
configuration''. |
|
|
369 |
|
|
|
370 |
|
|
|
371 |
__Permanently fixing your system's locale |
|
|
372 |
configuration__ |
|
|
373 |
|
|
|
374 |
|
|
|
375 |
This is when you see something like: |
|
|
376 |
|
|
|
377 |
|
|
|
378 |
perl: warning: Please check that your locale settings: |
|
|
379 |
LC_ALL = |
|
|
380 |
but then cannot see that ``En_US'' listed by the above-mentioned commands. You may see things like ``en_US.ISO8859-1'', but that isn't the same. In this case, try running under a locale that you can list and which somehow matches what you tried. The rules for matching locale names are a bit vague because standardization is weak in this area. See again the ``Finding locales'' about general rules. |
|
|
381 |
|
|
|
382 |
|
|
|
383 |
__Fixing system locale configuration__ |
|
|
384 |
|
|
|
385 |
|
|
|
386 |
Contact a system administrator (preferably your own) and |
|
|
387 |
report the exact error message you get, and ask them to read |
|
|
388 |
this same documentation you are now reading. They should be |
|
|
389 |
able to check whether there is something wrong with the |
|
|
390 |
locale configuration of the system. The ``Finding locales'' |
|
|
391 |
section is unfortunately a bit vague about the exact |
|
|
392 |
commands and places because these things are not that |
|
|
393 |
standardized. |
|
|
394 |
|
|
|
395 |
|
|
|
396 |
__The localeconv function__ |
|
|
397 |
|
|
|
398 |
|
|
|
399 |
The ''POSIX::localeconv()'' function allows you to get |
|
|
400 |
particulars of the locale-dependent numeric formatting |
|
|
401 |
information specified by the current LC_NUMERIC and |
|
|
402 |
LC_MONETARY locales. (If you just want the name of |
|
|
403 |
the current locale for a particular category, use |
|
|
404 |
''POSIX::setlocale()'' with a single parameter--see ``The |
|
|
405 |
setlocale function''.) |
|
|
406 |
|
|
|
407 |
|
|
|
408 |
use POSIX qw(locale_h); |
|
|
409 |
# Get a reference to a hash of locale-dependent info |
|
|
410 |
$locale_values = localeconv(); |
|
|
411 |
# Output sorted list of the values |
|
|
412 |
for (sort keys %$locale_values) { |
|
|
413 |
printf |
|
|
414 |
''localeconv()'' takes no arguments, and returns __a reference to__ a hash. The keys of this hash are variable names for formatting, such as decimal_point and thousands_sep. The values are the corresponding, er, values. See ``localeconv'' in POSIX for a longer example listing the categories an implementation might be expected to provide; some provide more and others fewer. You don't need an explicit use locale, because ''localeconv()'' always observes the current locale. |
|
|
415 |
|
|
|
416 |
|
|
|
417 |
Here's a simple-minded example program that rewrites its |
|
|
418 |
command-line parameters as integers correctly formatted in |
|
|
419 |
the current locale: |
|
|
420 |
|
|
|
421 |
|
|
|
422 |
# See comments in previous example |
|
|
423 |
require 5.004; |
|
|
424 |
use POSIX qw(locale_h); |
|
|
425 |
# Get some of locale's numeric formatting parameters |
|
|
426 |
my ($thousands_sep, $grouping) = |
|
|
427 |
@{localeconv()}{'thousands_sep', 'grouping'}; |
|
|
428 |
# Apply defaults if values are missing |
|
|
429 |
$thousands_sep = ',' unless $thousands_sep; |
|
|
430 |
# grouping and mon_grouping are packed lists |
|
|
431 |
# of small integers (characters) telling the |
|
|
432 |
# grouping (thousand_seps and mon_thousand_seps |
|
|
433 |
# being the group dividers) of numbers and |
|
|
434 |
# monetary quantities. The integers' meanings: |
|
|
435 |
# 255 means no more grouping, 0 means repeat |
|
|
436 |
# the previous grouping, 1-254 means use that |
|
|
437 |
# as the current grouping. Grouping goes from |
|
|
438 |
# right to left (low to high digits). In the |
|
|
439 |
# below we cheat slightly by never using anything |
|
|
440 |
# else than the first grouping (whatever that is). |
|
|
441 |
if ($grouping) { |
|
|
442 |
@grouping = unpack( |
|
|
443 |
# Format command line params for current locale |
|
|
444 |
for (@ARGV) { |
|
|
445 |
$_ = int; # Chop non-integer part |
|
|
446 |
1 while |
|
|
447 |
s/(d)(d{$grouping[[0]}($$thousands_sep))/$1$thousands_sep$2/; |
|
|
448 |
print |
|
|
449 |
!!LOCALE CATEGORIES |
|
|
450 |
|
|
|
451 |
|
|
|
452 |
The following subsections describe basic locale categories. |
|
|
453 |
Beyond these, some combination categories allow manipulation |
|
|
454 |
of more than one basic category at a time. See `` |
|
|
455 |
ENVIRONMENT '' for a discussion of |
|
|
456 |
these. |
|
|
457 |
|
|
|
458 |
|
|
|
459 |
__Category LC_COLLATE: |
|
|
460 |
Collation__ |
|
|
461 |
|
|
|
462 |
|
|
|
463 |
In the scope of use locale, Perl looks to the |
|
|
464 |
LC_COLLATE environment variable to determine the |
|
|
465 |
application's notions on collation (ordering) of characters. |
|
|
466 |
For example, 'b' follows 'a' in Latin alphabets, but where |
|
|
467 |
do 'a' and 'aa' belong? And while 'color' follows |
|
|
468 |
'chocolate' in English, what about in Spanish? |
|
|
469 |
|
|
|
470 |
|
|
|
471 |
The following collations all make sense and you may meet any |
|
|
472 |
of them if you ``use locale''. |
|
|
473 |
|
|
|
474 |
|
|
|
475 |
A B C D E a b c d e |
|
|
476 |
A a B b C c D d E e |
|
|
477 |
a A b B c C d D e E |
|
|
478 |
a b c d e A B C D E |
|
|
479 |
Here is a code snippet to tell what ``word'' characters are in the current locale, in that locale's order: |
|
|
480 |
|
|
|
481 |
|
|
|
482 |
use locale; |
|
|
483 |
print +(sort grep /w/, map { chr } 0..255), |
|
|
484 |
Compare this with the characters that you see and their order if you state explicitly that the locale should be ignored: |
|
|
485 |
|
|
|
486 |
|
|
|
487 |
no locale; |
|
|
488 |
print +(sort grep /w/, map { chr } 0..255), |
|
|
489 |
This machine-native collation (which is what you get unless use locale has appeared earlier in the same block) must be used for sorting raw binary data, whereas the locale-dependent collation of the first example is useful for natural text. |
|
|
490 |
|
|
|
491 |
|
|
|
492 |
As noted in `` USING LOCALES '', cmp |
|
|
493 |
compares according to the current collation locale when |
|
|
494 |
use locale is in effect, but falls back to a |
|
|
495 |
byte-by-byte comparison for strings that the locale says are |
|
|
496 |
equal. You can use ''POSIX::strcoll()'' if you don't want |
|
|
497 |
this fall-back: |
|
|
498 |
|
|
|
499 |
|
|
|
500 |
use POSIX qw(strcoll); |
|
|
501 |
$equal_in_locale = |
|
|
502 |
!strcoll( |
|
|
503 |
$equal_in_locale will be true if the collation locale specifies a dictionary-like ordering that ignores space characters completely and which folds case. |
|
|
504 |
|
|
|
505 |
|
|
|
506 |
If you have a single string that you want to check for |
|
|
507 |
``equality in locale'' against several others, you might |
|
|
508 |
think you could gain a little efficiency by using |
|
|
509 |
''POSIX::strxfrm()'' in conjunction with |
|
|
510 |
eq: |
|
|
511 |
|
|
|
512 |
|
|
|
513 |
use POSIX qw(strxfrm); |
|
|
514 |
$xfrm_string = strxfrm( |
|
|
515 |
''strxfrm()'' takes a string and maps it into a transformed string for use in byte-by-byte comparisons against other transformed strings during collation. ``Under the hood'', locale-affected Perl comparison operators call ''strxfrm()'' for both operands, then do a byte-by-byte comparison of the transformed strings. By calling ''strxfrm()'' explicitly and using a non locale-affected comparison, the example attempts to save a couple of transformations. But in fact, it doesn't save anything: Perl magic (see ``Magic Variables'' in perlguts) creates the transformed version of a string the first time it's needed in a comparison, then keeps this version around in case it's needed again. An example rewritten the easy way with cmp runs just about as fast. It also copes with null characters embedded in strings; if you call ''strxfrm()'' directly, it treats the first null it finds as a terminator. don't expect the transformed strings it produces to be portable across systems--or even from one revision of your operating system to the next. In short, don't call ''strxfrm()'' directly: let Perl do it for you. |
|
|
516 |
|
|
|
517 |
|
|
|
518 |
Note: use locale isn't shown in some of these |
|
|
519 |
examples because it isn't needed: ''strcoll()'' and |
|
|
520 |
''strxfrm()'' exist only to generate locale-dependent |
|
|
521 |
results, and so always obey the current LC_COLLATE |
|
|
522 |
locale. |
|
|
523 |
|
|
|
524 |
|
|
|
525 |
__Category LC_CTYPE: Character |
|
|
526 |
Types__ |
|
|
527 |
|
|
|
528 |
|
|
|
529 |
In the scope of use locale, Perl obeys the |
|
|
530 |
LC_CTYPE locale setting. This controls the |
|
|
531 |
application's notion of which characters are alphabetic. |
|
|
532 |
This affects Perl's w regular expression |
|
|
533 |
metanotation, which stands for alphanumeric characters--that |
|
|
534 |
is, alphabetic, numeric, and including other special |
|
|
535 |
characters such as the underscore or hyphen. (Consult perlre |
|
|
536 |
for more information about regular expressions.) Thanks to |
|
|
537 |
LC_CTYPE, depending on your locale setting, |
|
|
538 |
characters like 'ae', 'd', 'ss', and 'o/' may be understood |
|
|
539 |
as w characters. |
|
|
540 |
|
|
|
541 |
|
|
|
542 |
The LC_CTYPE locale also provides the map used in |
|
|
543 |
transliterating characters between lower and uppercase. This |
|
|
544 |
affects the case-mapping functions--''lc()'', lcfirst, |
|
|
545 |
''uc()'', and ''ucfirst()''; case-mapping |
|
|
546 |
interpolation with l, L, u, or |
|
|
547 |
U in double-quoted strings and s/// |
|
|
548 |
substitutions; and case-independent regular expression |
|
|
549 |
pattern matching using the i modifier. |
|
|
550 |
|
|
|
551 |
|
|
|
552 |
Finally, LC_CTYPE affects the POSIX |
|
|
553 |
character-class test functions--''isalpha()'', |
|
|
554 |
''islower()'', and so on. For example, if you move from |
|
|
555 |
the ``C'' locale to a 7-bit Scandinavian one, you may |
|
|
556 |
find--possibly to your surprise--that ``'' moves from the |
|
|
557 |
''ispunct()'' class to ''isalpha()''. |
|
|
558 |
|
|
|
559 |
|
|
|
560 |
__Note:__ A broken or malicious LC_CTYPE locale |
|
|
561 |
definition may result in clearly ineligible characters being |
|
|
562 |
considered to be alphanumeric by your application. For |
|
|
563 |
strict matching of (mundane) letters and digits--for |
|
|
564 |
example, in command strings--locale-aware applications |
|
|
565 |
should use w inside a no locale block. See |
|
|
566 |
`` SECURITY ''. |
|
|
567 |
|
|
|
568 |
|
|
|
569 |
__Category LC_NUMERIC: Numeric |
|
|
570 |
Formatting__ |
|
|
571 |
|
|
|
572 |
|
|
|
573 |
In the scope of use locale, Perl obeys the |
|
|
574 |
LC_NUMERIC locale information, which controls an |
|
|
575 |
application's idea of how numbers should be formatted for |
|
|
576 |
human readability by the ''printf()'', ''sprintf()'', |
|
|
577 |
and ''write()'' functions. String-to-numeric conversion |
|
|
578 |
by the ''POSIX::strtod()'' function is also affected. In |
|
|
579 |
most implementations the only effect is to change the |
|
|
580 |
character used for the decimal point--perhaps from '.' to |
|
|
581 |
','. These functions aren't aware of such niceties as |
|
|
582 |
thousands separation and so on. (See ``The localeconv |
|
|
583 |
function'' if you care about these things.) |
|
|
584 |
|
|
|
585 |
|
|
|
586 |
Output produced by ''print()'' is also affected by the |
|
|
587 |
current locale: it depends on whether use locale or |
|
|
588 |
no locale is in effect, and corresponds to what |
|
|
589 |
you'd get from ''printf()'' in the ``C'' locale. The same |
|
|
590 |
is true for Perl's internal conversions between numeric and |
|
|
591 |
string formats: |
|
|
592 |
|
|
|
593 |
|
|
|
594 |
use POSIX qw(strtod); |
|
|
595 |
use locale; |
|
|
596 |
$n = 5/2; # Assign numeric 2.5 to $n |
|
|
597 |
$a = |
|
|
598 |
print |
|
|
599 |
printf |
|
|
600 |
print |
|
|
601 |
|
|
|
602 |
|
|
|
603 |
__Category LC_MONETARY: Formatting of |
|
|
604 |
monetary amounts__ |
|
|
605 |
|
|
|
606 |
|
|
|
607 |
The C standard defines the LC_MONETARY category, |
|
|
608 |
but no function that is affected by its contents. (Those |
|
|
609 |
with experience of standards committees will recognize that |
|
|
610 |
the working group decided to punt on the issue.) |
|
|
611 |
Consequently, Perl takes no notice of it. If you really want |
|
|
612 |
to use LC_MONETARY, you can query its contents--see |
|
|
613 |
``The localeconv function''--and use the information that it |
|
|
614 |
returns in your application's own formatting of currency |
|
|
615 |
amounts. However, you may well find that the information, |
|
|
616 |
voluminous and complex though it may be, still does not |
|
|
617 |
quite meet your requirements: currency formatting is a hard |
|
|
618 |
nut to crack. |
|
|
619 |
|
|
|
620 |
|
|
|
621 |
__LC_TIME__ |
|
|
622 |
|
|
|
623 |
|
|
|
624 |
Output produced by ''POSIX::strftime()'', which builds a |
|
|
625 |
formatted human-readable date/time string, is affected by |
|
|
626 |
the current LC_TIME locale. Thus, in a French |
|
|
627 |
locale, the output produced by the %B format |
|
|
628 |
element (full month name) for the first month of the year |
|
|
629 |
would be ``janvier''. Here's how to get a list of long month |
|
|
630 |
names in the current locale: |
|
|
631 |
|
|
|
632 |
|
|
|
633 |
use POSIX qw(strftime); |
|
|
634 |
for (0..11) { |
|
|
635 |
$long_month_name[[$_] = |
|
|
636 |
strftime( |
|
|
637 |
Note: use locale isn't needed in this example: as a function that exists only to generate locale-dependent results, ''strftime()'' always obeys the current LC_TIME locale. |
|
|
638 |
|
|
|
639 |
|
|
|
640 |
__Other categories__ |
|
|
641 |
|
|
|
642 |
|
|
|
643 |
The remaining locale category, LC_MESSAGES |
|
|
644 |
(possibly supplemented by others in particular |
|
|
645 |
implementations) is not currently used by Perl--except |
|
|
646 |
possibly to affect the behavior of library functions called |
|
|
647 |
by extensions outside the standard Perl distribution and by |
|
|
648 |
the operating system and its utilities. Note especially that |
|
|
649 |
the string value of $! and the error messages given |
|
|
650 |
by external utilities may be changed by |
|
|
651 |
LC_MESSAGES. If you want to have portable error |
|
|
652 |
codes, use %!. See Errno. |
|
|
653 |
!!SECURITY |
|
|
654 |
|
|
|
655 |
|
|
|
656 |
Although the main discussion of Perl security issues can be |
|
|
657 |
found in perlsec, a discussion of Perl's locale handling |
|
|
658 |
would be incomplete if it did not draw your attention to |
|
|
659 |
locale-dependent security issues. Locales--particularly on |
|
|
660 |
systems that allow unprivileged users to build their own |
|
|
661 |
locales--are untrustworthy. A malicious (or just plain |
|
|
662 |
broken) locale can make a locale-aware application give |
|
|
663 |
unexpected results. Here are a few |
|
|
664 |
possibilities: |
|
|
665 |
|
|
|
666 |
|
|
|
667 |
Regular expression checks for safe file names or mail |
|
|
668 |
addresses using w may be spoofed by an |
|
|
669 |
LC_CTYPE locale that claims that characters such as |
|
|
670 |
|
|
|
671 |
|
|
|
672 |
String interpolation with case-mapping, as in, say, |
|
|
673 |
$dest = , may produce |
|
|
674 |
dangerous results if a bogus LC_CTYPE |
|
|
675 |
case-mapping table is in effect. |
|
|
676 |
|
|
|
677 |
|
|
|
678 |
A sneaky LC_COLLATE locale could result in the |
|
|
679 |
names of students with ``D'' grades appearing ahead of those |
|
|
680 |
with ``A''s. |
|
|
681 |
|
|
|
682 |
|
|
|
683 |
An application that takes the trouble to use information in |
|
|
684 |
LC_MONETARY may format debits as if they were |
|
|
685 |
credits and vice versa if that locale has been subverted. Or |
|
|
686 |
it might make payments in US dollars instead |
|
|
687 |
of Hong Kong dollars. |
|
|
688 |
|
|
|
689 |
|
|
|
690 |
The date and day names in dates formatted by |
|
|
691 |
''strftime()'' could be manipulated to advantage by a |
|
|
692 |
malicious user able to subvert the LC_DATE locale. |
|
|
693 |
(``Look--it says I wasn't in the building on |
|
|
694 |
Sunday.'') |
|
|
695 |
|
|
|
696 |
|
|
|
697 |
Such dangers are not peculiar to the locale system: any |
|
|
698 |
aspect of an application's environment which may be modified |
|
|
699 |
maliciously presents similar challenges. Similarly, they are |
|
|
700 |
not specific to Perl: any programming language that allows |
|
|
701 |
you to write programs that take account of their environment |
|
|
702 |
exposes you to these issues. |
|
|
703 |
|
|
|
704 |
|
|
|
705 |
Perl cannot protect you from all possibilities shown in the |
|
|
706 |
examples--there is no substitute for your own |
|
|
707 |
vigilance--but, when use locale is in effect, Perl |
|
|
708 |
uses the tainting mechanism (see perlsec) to mark string |
|
|
709 |
results that become locale-dependent, and which may be |
|
|
710 |
untrustworthy in consequence. Here is a summary of the |
|
|
711 |
tainting behavior of operators and functions that may be |
|
|
712 |
affected by the locale: |
|
|
713 |
|
|
|
714 |
|
|
|
715 |
__Comparison operators__ (lt, le, |
|
|
716 |
ge, gt and cmp): |
|
|
717 |
|
|
|
718 |
|
|
|
719 |
Scalar true/false (or less/equal/greater) result is never |
|
|
720 |
tainted. |
|
|
721 |
|
|
|
722 |
|
|
|
723 |
__Case-mapping interpolation__ (with l, |
|
|
724 |
L, u or U) |
|
|
725 |
|
|
|
726 |
|
|
|
727 |
Result string containing interpolated material is tainted if |
|
|
728 |
use locale is in effect. |
|
|
729 |
|
|
|
730 |
|
|
|
731 |
__Matching operator__ (m//): |
|
|
732 |
|
|
|
733 |
|
|
|
734 |
Scalar true/false result never tainted. |
|
|
735 |
|
|
|
736 |
|
|
|
737 |
Subpatterns, either delivered as a list-context result or as |
|
|
738 |
$1 etc. are tainted if use locale is in |
|
|
739 |
effect, and the subpattern regular expression contains |
|
|
740 |
w (to match an alphanumeric character), W |
|
|
741 |
(non-alphanumeric character), s (white-space |
|
|
742 |
character), or S (non white-space character). The |
|
|
743 |
matched-pattern variable, $ |
|
|
744 |
use locale is in effect and the regular expression |
|
|
745 |
contains w, W, s, or |
|
|
746 |
S. |
|
|
747 |
|
|
|
748 |
|
|
|
749 |
__Substitution operator__ (s///): |
|
|
750 |
|
|
|
751 |
|
|
|
752 |
Has the same behavior as the match operator. Also, the left |
|
|
753 |
operand of =~ becomes tainted when use |
|
|
754 |
locale in effect if modified as a result of a |
|
|
755 |
substitution based on a regular expression match involving |
|
|
756 |
w, W, s, or S; or of |
|
|
757 |
case-mapping with l, L,u or |
|
|
758 |
U. |
|
|
759 |
|
|
|
760 |
|
|
|
761 |
__Output formatting functions__ (''printf()'' and |
|
|
762 |
''write()''): |
|
|
763 |
|
|
|
764 |
|
|
|
765 |
Results are never tainted because otherwise even output from |
|
|
766 |
print, for example print(1/7), should be tainted if |
|
|
767 |
use locale is in effect. |
|
|
768 |
|
|
|
769 |
|
|
|
770 |
__Case-mapping functions__ (''lc()'', |
|
|
771 |
''lcfirst()'', ''uc()'', |
|
|
772 |
''ucfirst()''): |
|
|
773 |
|
|
|
774 |
|
|
|
775 |
Results are tainted if use locale is in |
|
|
776 |
effect. |
|
|
777 |
|
|
|
778 |
|
|
|
779 |
__POSIX locale-dependent functions__ |
|
|
780 |
(''localeconv()'', ''strcoll()'', ''strftime()'', |
|
|
781 |
''strxfrm()''): |
|
|
782 |
|
|
|
783 |
|
|
|
784 |
Results are never tainted. |
|
|
785 |
|
|
|
786 |
|
|
|
787 |
__POSIX character class tests__ |
|
|
788 |
(''isalnum()'', ''isalpha()'', ''isdigit()'', |
|
|
789 |
''isgraph()'', ''islower()'', ''isprint()'', |
|
|
790 |
''ispunct()'', ''isspace()'', ''isupper()'', |
|
|
791 |
''isxdigit()''): |
|
|
792 |
|
|
|
793 |
|
|
|
794 |
True/false results are never tainted. |
|
|
795 |
|
|
|
796 |
|
|
|
797 |
Three examples illustrate locale-dependent tainting. The |
|
|
798 |
first program, which ignores its locale, won't run: a value |
|
|
799 |
taken directly from the command line may not be used to name |
|
|
800 |
an output file when taint checks are enabled. |
|
|
801 |
|
|
|
802 |
|
|
|
803 |
#/usr/local/bin/perl -T |
|
|
804 |
# Run with taint checking |
|
|
805 |
# Command line sanity check omitted... |
|
|
806 |
$tainted_output_file = shift; |
|
|
807 |
open(F, |
|
|
808 |
The program can be made to run by ``laundering'' the tainted value through a regular expression: the second example--which still ignores locale information--runs, creating the file named on its command line if it can. |
|
|
809 |
|
|
|
810 |
|
|
|
811 |
#/usr/local/bin/perl -T |
|
|
812 |
$tainted_output_file = shift; |
|
|
813 |
$tainted_output_file =~ m%[[w/]+%; |
|
|
814 |
$untainted_output_file = $ |
|
|
815 |
open(F, |
|
|
816 |
Compare this with a similar but locale-aware program: |
|
|
817 |
|
|
|
818 |
|
|
|
819 |
#/usr/local/bin/perl -T |
|
|
820 |
$tainted_output_file = shift; |
|
|
821 |
use locale; |
|
|
822 |
$tainted_output_file =~ m%[[w/]+%; |
|
|
823 |
$localized_output_file = $ |
|
|
824 |
open(F, |
|
|
825 |
This third program fails to run because $w while use locale is in effect. |
|
|
826 |
!!ENVIRONMENT |
|
|
827 |
|
|
|
828 |
|
|
|
829 |
PERL_BADLANG |
|
|
830 |
|
|
|
831 |
|
|
|
832 |
A string that can suppress Perl's warning about failed |
|
|
833 |
locale settings at startup. Failure can occur if the locale |
|
|
834 |
support in the operating system is lacking (broken) in some |
|
|
835 |
way--or if you mistyped the name of a locale when you set up |
|
|
836 |
your environment. If this environment variable is absent, or |
|
|
837 |
has a value that does not evaluate to integer zero--that is, |
|
|
838 |
``0'' or |
|
|
839 |
|
|
|
840 |
|
|
|
841 |
__NOTE__ : PERL_BADLANG |
|
|
842 |
only gives you a way to hide the warning message. The |
|
|
843 |
message tells about some problem in your system's locale |
|
|
844 |
support, and you should investigate what the problem |
|
|
845 |
is. |
|
|
846 |
|
|
|
847 |
|
|
|
848 |
The following environment variables are not specific to |
|
|
849 |
Perl: They are part of the standardized ( ISO |
|
|
850 |
C, XPG4 , POSIX 1.c) |
|
|
851 |
''setlocale()'' method for controlling an application's |
|
|
852 |
opinion on data. |
|
|
853 |
|
|
|
854 |
|
|
|
855 |
LC_ALL |
|
|
856 |
|
|
|
857 |
|
|
|
858 |
LC_ALL is the ``override-all'' locale environment |
|
|
859 |
variable. If set, it overrides all the rest of the locale |
|
|
860 |
environment variables. |
|
|
861 |
|
|
|
862 |
|
|
|
863 |
LANGUAGE |
|
|
864 |
|
|
|
865 |
|
|
|
866 |
__NOTE__ : LANGUAGE is a |
|
|
867 |
GNU extension, it affects you only if you are |
|
|
868 |
using the GNU libc. This is the case if you |
|
|
869 |
are using e.g. Linux. If you are using ``commercial'' UNIXes |
|
|
870 |
you are most probably ''not'' using GNU |
|
|
871 |
libc and you can ignore LANGUAGE. |
|
|
872 |
|
|
|
873 |
|
|
|
874 |
However, in the case you are using LANGUAGE: it |
|
|
875 |
affects the language of informational, warning, and error |
|
|
876 |
messages output by commands (in other words, it's like |
|
|
877 |
LC_MESSAGES) but it has higher priority than |
|
|
878 |
LC_ALL . Moreover, it's not a single value |
|
|
879 |
but instead a ``path'' (``:''-separated list) of |
|
|
880 |
''languages'' (not locales). See the GNU |
|
|
881 |
gettext library documentation for more |
|
|
882 |
information. |
|
|
883 |
|
|
|
884 |
|
|
|
885 |
LC_CTYPE |
|
|
886 |
|
|
|
887 |
|
|
|
888 |
In the absence of LC_ALL, LC_CTYPE chooses |
|
|
889 |
the character type locale. In the absence of both |
|
|
890 |
LC_ALL and LC_CTYPE, LANG chooses |
|
|
891 |
the character type locale. |
|
|
892 |
|
|
|
893 |
|
|
|
894 |
LC_COLLATE |
|
|
895 |
|
|
|
896 |
|
|
|
897 |
In the absence of LC_ALL, LC_COLLATE |
|
|
898 |
chooses the collation (sorting) locale. In the absence of |
|
|
899 |
both LC_ALL and LC_COLLATE, LANG |
|
|
900 |
chooses the collation locale. |
|
|
901 |
|
|
|
902 |
|
|
|
903 |
LC_MONETARY |
|
|
904 |
|
|
|
905 |
|
|
|
906 |
In the absence of LC_ALL, LC_MONETARY |
|
|
907 |
chooses the monetary formatting locale. In the absence of |
|
|
908 |
both LC_ALL and LC_MONETARY, LANG |
|
|
909 |
chooses the monetary formatting locale. |
|
|
910 |
|
|
|
911 |
|
|
|
912 |
LC_NUMERIC |
|
|
913 |
|
|
|
914 |
|
|
|
915 |
In the absence of LC_ALL, LC_NUMERIC |
|
|
916 |
chooses the numeric format locale. In the absence of both |
|
|
917 |
LC_ALL and LC_NUMERIC, LANG |
|
|
918 |
chooses the numeric format. |
|
|
919 |
|
|
|
920 |
|
|
|
921 |
LC_TIME |
|
|
922 |
|
|
|
923 |
|
|
|
924 |
In the absence of LC_ALL, LC_TIME chooses |
|
|
925 |
the date and time formatting locale. In the absence of both |
|
|
926 |
LC_ALL and LC_TIME, LANG chooses |
|
|
927 |
the date and time formatting locale. |
|
|
928 |
|
|
|
929 |
|
|
|
930 |
LANG LANG is the ``catch-all'' |
|
|
931 |
locale environment variable. If it is set, it is used as the |
|
|
932 |
last resort after the overall LC_ALL and the |
|
|
933 |
category-specific LC_.... |
|
|
934 |
!!NOTES |
|
|
935 |
|
|
|
936 |
|
|
|
937 |
__Backward compatibility__ |
|
|
938 |
|
|
|
939 |
|
|
|
940 |
Versions of Perl prior to 5.004 __mostly__ ignored locale |
|
|
941 |
information, generally behaving as if something similar to |
|
|
942 |
the locale were always in force, even |
|
|
943 |
if the program environment suggested otherwise (see ``The |
|
|
944 |
setlocale function''). By default, Perl still behaves this |
|
|
945 |
way for backward compatibility. If you want a Perl |
|
|
946 |
application to pay attention to locale information, you |
|
|
947 |
__must__ use the use locale pragma (see ``The |
|
|
948 |
use locale pragma'') to instruct it to do so. |
|
|
949 |
|
|
|
950 |
|
|
|
951 |
Versions of Perl from 5.002 to 5.003 did use the |
|
|
952 |
LC_CTYPE information if available; that is, |
|
|
953 |
w did understand what were the letters according to |
|
|
954 |
the locale environment variables. The problem was that the |
|
|
955 |
user had no control over the feature: if the C library |
|
|
956 |
supported locales, Perl used them. |
|
|
957 |
|
|
|
958 |
|
|
|
959 |
__I18N:Collate obsolete__ |
|
|
960 |
|
|
|
961 |
|
|
|
962 |
In versions of Perl prior to 5.004, per-locale collation was |
|
|
963 |
possible using the I18N::Collate library module. |
|
|
964 |
This module is now mildly obsolete and should be avoided in |
|
|
965 |
new applications. The LC_COLLATE functionality is |
|
|
966 |
now integrated into the Perl core language: One can use |
|
|
967 |
locale-specific scalar data completely normally with use |
|
|
968 |
locale, so there is no longer any need to juggle with |
|
|
969 |
the scalar references of |
|
|
970 |
I18N::Collate. |
|
|
971 |
|
|
|
972 |
|
|
|
973 |
__Sort speed and memory use impacts__ |
|
|
974 |
|
|
|
975 |
|
|
|
976 |
Comparing and sorting by locale is usually slower than the |
|
|
977 |
default sorting; slow-downs of two to four times have been |
|
|
978 |
observed. It will also consume more memory: once a Perl |
|
|
979 |
scalar variable has participated in any string comparison or |
|
|
980 |
sorting operation obeying the locale collation rules, it |
|
|
981 |
will take 3-15 times more memory than before. (The exact |
|
|
982 |
multiplier depends on the string's contents, the operating |
|
|
983 |
system and the locale.) These downsides are dictated more by |
|
|
984 |
the operating system's implementation of the locale system |
|
|
985 |
than by Perl. |
|
|
986 |
|
|
|
987 |
|
|
|
988 |
''write()'' __and |
|
|
989 |
LC_NUMERIC__ |
|
|
990 |
|
|
|
991 |
|
|
|
992 |
Formats are the only part of Perl that unconditionally use |
|
|
993 |
information from a program's locale; if a program's |
|
|
994 |
environment specifies an LC_NUMERIC locale, |
|
|
995 |
it is always used to specify the decimal point character in |
|
|
996 |
formatted output. Formatted output cannot be controlled by |
|
|
997 |
use locale because the pragma is tied to the block |
|
|
998 |
structure of the program, and, for historical reasons, |
|
|
999 |
formats exist outside that block structure. |
|
|
1000 |
|
|
|
1001 |
|
|
|
1002 |
__Freely available locale definitions__ |
|
|
1003 |
|
|
|
1004 |
|
|
|
1005 |
There is a large collection of locale definitions at |
|
|
1006 |
ftp://dkuug.dk/i18n/WG15-collection. You should be |
|
|
1007 |
aware that it is unsupported, and is not claimed to be fit |
|
|
1008 |
for any purpose. If your system allows installation of |
|
|
1009 |
arbitrary locales, you may find the definitions useful as |
|
|
1010 |
they are, or as a basis for the development of your own |
|
|
1011 |
locales. |
|
|
1012 |
|
|
|
1013 |
|
|
|
1014 |
__I18n and l10n__ |
|
|
1015 |
|
|
|
1016 |
|
|
|
1017 |
``Internationalization'' is often abbreviated as __i18n__ |
|
|
1018 |
because its first and last letters are separated by eighteen |
|
|
1019 |
others. (You may guess why the internalin ... internaliti |
|
|
1020 |
... i18n tends to get abbreviated.) In the same way, |
|
|
1021 |
``localization'' is often abbreviated to |
|
|
1022 |
__l10n__. |
|
|
1023 |
|
|
|
1024 |
|
|
|
1025 |
__An imperfect standard__ |
|
|
1026 |
|
|
|
1027 |
|
|
|
1028 |
Internationalization, as defined in the C and |
|
|
1029 |
POSIX standards, can be criticized as |
|
|
1030 |
incomplete, ungainly, and having too large a granularity. |
|
|
1031 |
(Locales apply to a whole process, when it would arguably be |
|
|
1032 |
more useful to have them apply to a single thread, window |
|
|
1033 |
group, or whatever.) They also have a tendency, like |
|
|
1034 |
standards groups, to divide the world into nations, when we |
|
|
1035 |
all know that the world can equally well be divided into |
|
|
1036 |
bankers, bikers, gamers, and so on. But, for now, it's the |
|
|
1037 |
only standard we've got. This may be construed as a |
|
|
1038 |
bug. |
|
|
1039 |
!!BUGS |
|
|
1040 |
|
|
|
1041 |
|
|
|
1042 |
__Broken systems__ |
|
|
1043 |
|
|
|
1044 |
|
|
|
1045 |
In certain systems, the operating system's locale support is |
|
|
1046 |
broken and cannot be fixed or used by Perl. Such |
|
|
1047 |
deficiencies can and will result in mysterious hangs and/or |
|
|
1048 |
Perl core dumps when the use locale is in effect. |
|
|
1049 |
When confronted with such a system, please report in |
|
|
1050 |
excruciating detail to perlbug@perl.org'' |
|
|
1051 |
'' |
|
|
1052 |
!!SEE ALSO |
|
|
1053 |
|
|
|
1054 |
|
|
|
1055 |
``isalnum'' in POSIX , ``isalpha'' in |
|
|
1056 |
POSIX , ``isdigit'' in POSIX , |
|
|
1057 |
``isgraph'' in POSIX , ``islower'' in |
|
|
1058 |
POSIX , ``isprint'' in POSIX , |
|
|
1059 |
``ispunct'' in POSIX , ``isspace'' in |
|
|
1060 |
POSIX , ``isupper'' in POSIX , |
|
|
1061 |
``isxdigit'' in POSIX , ``localeconv'' in |
|
|
1062 |
POSIX , ``setlocale'' in POSIX |
|
|
1063 |
, ``strcoll'' in POSIX , ``strftime'' in |
|
|
1064 |
POSIX , ``strtod'' in POSIX , |
|
|
1065 |
``strxfrm'' in POSIX . |
|
|
1066 |
!!HISTORY |
|
|
1067 |
|
|
|
1068 |
|
|
|
1069 |
Jarkko Hietaniemi's original ''perli18n.pod'' heavily |
|
|
1070 |
hacked by Dominic Dunlop, assisted by the perl5-porters. |
|
|
1071 |
Prose worked over a bit by Tom Christiansen. |
|
|
1072 |
|
|
|
1073 |
|
|
|
1074 |
Last update: Thu Jun 11 08:44:13 MDT |
|
|
1075 |
1998 |
|
|
1076 |
---- |