Using [package.]module prefix

Resolve symbol name conflicts with module prefix.

If a symbol is defined twice with the same name in two different modules, the symbol must be qualified by the name of the module or the package name, when the module belongs to a package.

This feature overcomes the traditional 4GL limitation, requiring unique function names within a program.

In the following example, both imported modules define the same "init()" function, but this can be resolved, by adding the module name followed by a dot before the function names:

IMPORT FGL orders 
IMPORT FGL customers 
MAIN
  CALL orders.init()
  CALL customers.init()
  ...
END MAIN

If a symbol is defined twice with the same name in the current and the imported module, an unqualified symbol will reference the current module symbol.

The following example calls the "init()" function with and without a module qualifier. The second call will reference the local function:

IMPORT FGL orders 
MAIN
  CALL orders.init()  -- orders module function 
  CALL init()  -- local function 
  ...
END MAIN
FUNCTION init()
  ...
END FUNCTION

IMPORT FGL myshop.* -- imports several modules including "orders"
MAIN
  CALL myshop.orders.init() 
  ...
END MAIN

To make the code more readable, check for unqualified symbols with the -W unqualified-imports warning, and consider using the --qualify-imports option of fglcomp to refactor the sources.

The --qualify-imports option is part of the code refactoring tools provided by Genero BDL.

For more details, see Qualifying imported symbols.