Syntax
=====

.. code-block:: text

    char_acou = AFFE_CHAR_ACOU (
        ◆ MODELE = model,
        ◇ DOUBLE_LAGRANGE = "OUI ",
        ◆ | PRES_IMPO = _F (
               ◆ | ALL = "YES" (or not specified),
                 | GROUP_MA = grma,
                 | GROUP_NO = group,
               ◇ SANS_GROUP_MA = Grma,
               ◇ SANS_GROUP_NO = big,
               ◆ PRES = complex,
            ),
          | SPEED_FACE = _F (
               ◆ GROUP_MA = Grma,
               ◆/VNOR = complex,
            ),
          | UNIF_LINK = _F (
               ◆/GROUP_NO = grno,
                 /GROUP_MA = grma,
               ◆ DDL = "PRES" (or not specified),
            ),
    )
    
    ◆: mandatory
    ◇: optional
    : present by default
    &: together
    /: only one among
    |: several possible choices