Syntax
=====

.. code-block:: text

    cham_elem = CALC_CHAM_ELEM (
        ◆ MODELE = model,
        ◇/TOUT = "OUI" (or not specified),
          /GROUP_MA = grma,
        ◇ INST = float,
        ◇ MODE_FOURIER = int,
        ◆ OPTION =/"FLUX_ELGA ",
                   /"FLUX_ELNO ",
                   /"PRAC_ELNO ",
                   /"COOR_ELGA ",
                   /"ROCH_ELNO ",
        # If: equal_to (" OPTION ", 'ROCH_ELNO')
            ◆ CHAM_MATER = cham_master,
            ◆ CARA_ELEM = cara_elem,
        # If: not equal_to (" OPTION ", 'ROCH_ELNO')
            ◇ CARA_ELEM = cara_elem,
        # If: is_in (" OPTION ", ('FLUX_ELNO', 'FLUX_ELGA',))
            ◆ TEMP = cham_no,
            ◆ CHAM_MATER = cham_master,
        # If: is_in (" OPTION ", ('PRAC_ELNO',))
            ◆ PRES = cham_no,
    )
    
    ◆: mandatory
    ◇: optional
    : present by default
    &: together
    /: only one among
    |: several possible choices