Syntax
=====

.. code-block:: text

    integer = DEFI_FICHIER (
        ◇ ACTION =/"ASSOCIER" (by default),
                   /"LIBERER ",
                   /"RESERVER ",
        # If: equal_to (" ACTION ", 'ASSOCIER')
            ◆ | UNIT = unit,
              | FILE = text,
            ◇ TYPE =/"ASCII" (by default),
                     /"BINARY ",
                     /"LIBRE ",
            # If: equal_to (" TYPE ", 'ASCII')
                ◇ ACCES =/"NEW" (by default),
                          /"APPEND ",
                          /"OLD ",
            # If: not equal_to (" TYPE ", 'ASCII')
                ◇ ACCES =/"NEW" (by default),
                          /"OLD ",
        # If: equal_to (" ACTION ", 'RESERVER')
            ◆ | UNIT = unit,
              | FILE = text,
            ◇ TYPE = "ASCII ",
            ◇ ACCES = "APPEND ",
        # If: equal_to (" ACTION ", 'LIBERER')
            ◆/UNITE = unit,
              /FICHIER = text,
        ◇ INFO =/1,
                 /2,
    )
    
    ◆: mandatory
    ◇: optional
    : present by default
    &: together
    /: only one among
    |: several possible choices