In contrast to included modules, true modules have some distinct properties that are shown in the list below.

The following listing is a brief sample of a true module.

{
   // This is a module called "Sample".
   // Therefore the file name MUST be Sample.ycp
   // The "module" statement makes the module accessible for 'import'.
   //
   module "Sample";

   // This is a local declaration.
   // It can only be 'seen' inside the module.
   //
   integer local_var = 42;

   // This is a global declaration.
   // It can be accessed from outside with the name space identifier 'Sample::'.
   //
   global integer global_var = 27;

   // This is a global function.
   // It has access to global_var *and* local_var.
   //
   global define sample_f () ``{ return local_var + global_var; }
}
	

The module above can be used with the import statement. The syntax for file inclusion with import is similar to include. The interpreter automatically appends “.ycp” to the filename and searches below /usr/lib/YaST2/modules. If the filename starts with “./”, the file is loaded from the local directory. The global declarations of the module can then be accessed with the name space identifier Sample::.

	Note
	The file name must match the module declaration! Inside modules, only variable or function declarations are allowed. Stand-alone blocks or any kind of evaluation statements are forbidden.

{
    // This imports the 'Sample'-module.
    //
    import "Sample";

    // The global function is called with the respective name space identifier.
    //
    integer i = Sample::sample_f();     // == 69

    // No access to local module variables.
    //
    i = Sample::local_var;              // ERROR, no access possible !

    // No problem with global variables.
    //
    i = Sample::global_var;             // == 27

    Sample::global_var = 0;             // This variable is writable !!

    return Sample::sample_f();          // == 42, since global_var is 0
}
	

	Note
	The first encounter of the statement import "Sample"; triggers the loading of “Sample.ycp”. Subsequent import statements are ignored, because “Sample” is already defined. Consequently you can't replace a module during runtime !