Subversion Repositories SvarDOS

              SVARLANG.LIB - THE SVARDOS TRANSLATION C LIBRARY

                   Copyright (C) 2021-2022 Mateusz Viste



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 SvarLANG calls, typically:

  svarlang_load("myprogram", "pl", "."); /* load .\myprogram.lng */
  puts(svarlang_str(2, 0));              /* display the string with id 2.0 */

Read svarlang.h for more information about available functions.


### DIRTY STRINGS ###

In the CATS-style source translation, lines may be prefixed with a '?' sign:

?1.1:Hello, World!

Such string is used by tlumacz like any other, but it is also reported on the
command-line with a warning about the line being "dirty" (that is, requiring
to be reviewed by a translator).


### ENVIRONMENT ###

The program translation file should be named "PROGNAME.LNG", where PROGNAME
is the program's name. This file should be placed in a well-known location,
typically the program's own directory. An exception are SvarDOS "CORE" programs
that store their translation files in a directory pointed out by %NLSPATH%.

The %LANG% environment variable usually defines what language should be loaded,
albeit the program can just as well provide its own controls for language
selection and pass this information to svarlang_load() accordingly.


### 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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