1. Write a message file

# greetings.msg
$MODULE greetings
$LANGUAGE en
$STRING ENABLE

$MESSAGE Welcome
@ user std::string const &
"Welcome, {$user}!"
[tr]
"Hoş geldin, {$user}!"
  • $MODULE names the output: greetings.hh and greetings.cpp.
  • $LANGUAGE en says the texts without a header are English.
  • $STRING ENABLE asks for a string function per message.
  • $MESSAGE Welcome has one parameter, user, and a text in English and Turkish; {$user} puts the parameter into the text.

2. Generate

mstring greetings.msg

// greetings.hh (excerpt)
std::string WelcomeStr( std::string const & user, std::locale const &loc );
std::string WelcomeStr( std::string const & user );

3. Use it

#include "greetings.hh"
#include <iostream>

int main( )
{
  std::cout << WelcomeStr( "Ada" ) << '\n';                  // Welcome, Ada!

  try
  {
    std::locale tr( "tr_TR.UTF-8" );
    std::cout << WelcomeStr( "Ada", tr ) << '\n';            // Hoş geldin, Ada!
  }
  catch ( std::runtime_error const & )                       // locale not installed
  {
  }
}

g++ -std=c++17 main.cpp greetings.cpp -o hello

WelcomeStr( 42 ) does not compile — the parameter is a string.

4. Let the build do it

In CMake, mstring_generate() runs mstring whenever the message file changes:

find_package(mstring REQUIRED)
mstring_generate(GREETINGS greetings.msg)
add_executable(hello main.cpp ${GREETINGS})
target_include_directories(hello PRIVATE ${CMAKE_CURRENT_BINARY_DIR})

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