Subversion Repositories SvarDOS

              SVARLANG.LIB - THE SVARDOS TRANSLATION C LIBRARY


SvarLANG is a library and tooling for enabling SvarDOS applications to easily
support multiple languages.


### PREPARING TRANSLATION FILES ###

The translation files must be CATS-style text files in the usual format:

1.1:Hello, World!
1.2:Help screen
2.0:Type /? for more options

The files must be named as EN.TXT, DE.TXT, FR.TXT, etc. Then, they must be
"compiled" into SvarLANG's binary format using the TLUMACZ tool:

tlumacz en fr pl (...)

The first language provided in the command line is the reference language and
is used both as the default (embedded in the application) language, as well as
to substitute messages missing in other languages.

TLUMACZ computes two files:

 * OUT.LNG   - the binary file that contains all translations
 * DEFLANG.C - the default translations that will be embedded into the program

Then, DEFLANG.C must be compiled and linked to your program along with
SVARLNGx.LIB. From there, you will be able to use the following calls:

/* loads translations for program PROGNAME, language LANG, in the path NLSPATH.
 * returns 0 on success. */
int svarlang_load(const char *progname, const char *lang, const char *nlspath);

/* same as svarlang_load(), but relies on getenv() to pull LANG and NLSPATH. */
int svarlang_autoload(const char *progname);

/* Returns a pointer to the string "id". Does not require svalang_load() to be
 * executed, but then it will only return the reference language strings.
 * a string id is the concatenation of the CATS-style identifiers, for example
 * string 1,0 becomes 0x0100, string 2.10 is 0x020A, etc. */
const char *svarlang_strid(unsigned short id);

/* a convenience definition to fetch strings by their CATS-style pairs instead
 * of the 16-bit id. */
#define svarlang_str(x, y) svarlang_strid((x << 8) | y)


### ENVIRONMENT ###

All translations files should be placed in the %NLSPATH% directory and should
be named the same as the program's name, with the LNG extension (for example
"INSTALL.LNG" if the program is named "INSTALL").

The %LANG% environment variable defines what language should be loaded.


### WHY IS IT BETTER THAN CATS? ###

The CATS library is heavier and slower, as it embeds a text-file parser.
Translations also take more disk space since each file is in a separate file
leading to cluster waste. Finally, CATS requires default strings to be part of
the application's source code, while SvarLANG keeps all strings in TXT files
and embedds the default one inside the application in an automated way at
compile time.

There is also a licensing issue: CATS/Kitten libraries are published under the
terms of a viral license. SvarLANG, on the other hand, is published under a
truly free, liberal license (MIT).


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