Multilingual applications

[Sergey Basalaev]

The first Alchemy application 'hello' now speaks 49 languages!

If you install latest hello package (version 3) and run it from the
terminal it will most probably print a message in your language.

You can also run it in different language changing the environment

variable LANGUAGE:

> env LANGUAGE=de hello

Hallo, welt!

To be honest, multilingual support was in Alchemy OS since release

2.1 but it was undocumented. Now with all needed tools written and

living example you can add multilingual support to your application!

Step 1: preparing source code

All you need is to do is to add header for internationalization (i18n for short)

use "i18n"

This is core header, no external libraries needed. Then just change every

"string" into _("string"). Function _( ) is the magic. Finally, you need to

tell your program which message catalog to use. To do that add this line

as the first line in main() function:

settextdomain("MyProgramName")

That's all. You can compile and run your application now. Of course, everything

will be in the original language because we have not created actual translations

yet.

Step 2: preparing translations

For that you will need to install i18n-tools package. This package currently

contains two utilities.

First of them, msgextract, used to extract all translatable strings from
your sources.

msgextract source1.e source2.e ... -o messages.txt

This will generate file messages.txt with contents like:

"String 1" = ""

"String 2" = ""

You need to put translations to your language after the '=' sign.

You can use this file as template and prepare translations to several

languages: de.txt, fr.txt, ru.txt ...

Step 3: compiling and installing translations

Finally, you need to turn prepared message catalogs into machine-readable

format and install them into appropriate locations.

Compiling is done by msgfmt utility, which is also in i18n-tools package

msgfmt ru.txt MyProgramName.lc

Here MyProgramName is exactly the string you used for settextdomain()

The default location for translations is /res/locale/<locale-code>/. For example,

Russian message catalogs will be put in /res/locale/ru/

install MyProgramName.lc /res/locale/ru/

[Kyle Alexander Buan]

Good! Can language be manually set by program without using env?

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[wiktorek140]

Yes. Throw function "setlocale()". But if u want hange language in any part of program u must use:
"
setlocale("de")
settextdomain("hello")
"
It is only simple. U can set your program name and language. I think it's only way to make program multilanguages in program, without env

[Kyle Alexander Buan]

Okay, thanks! :)

[Sergey Basalaev]

Yes, Wiktor is absolutely right.

I can add that the algorithm Alchemy uses to determine language

is the following:

1) Language set explicitely by setlocale(). Use this to change
language from within program.

2) If there is environment variable LANGUAGE - it is used. Use this

to launch external program in a different language.

3) If there is file /cfg/locale, language is read from that file. Use it to

set default language for all applications.

4) If nothing of above is applicable, alchemy reads system property

"microedition.locale" to set program language.