Syntax
=====

.. code-block:: text

    field_no = CALC_CHAR_SEISME (
        ◆ MATR_MASS = matr_asse_depl_r,
        ◆ DIRECTION = float,
        ◆/MONO_APPUI = "OUI" (or not specified),
          /MODE_STAT = meca fashion,
        # If: exists (" MODE_STAT ")
            ◆ GROUP_NO = grno,
        ◇ TITRE = text,
    )
    
    ◆: mandatory
    ◇: optional
    : present by default
    &: together
    /: only one among
    |: several possible choices