Syntax
=====

.. code-block:: text

    interspectrum = DYNA_ALEA_MODAL (
        ◆ BASE_MODALE = _F (
             ◆ MODE_MECA = meca fashion,
             ◆/BANDE = float,
               /NUME_ORDRE = int,
             # If: exists (" BANDE ")
                 ◆ AMOR_UNIF = float,
             # If: exists (" NUME_ORDRE ")
                 ◆ AMOR_REDUIT = float,
          ),
        ◇ MODE_STAT = meca fashion,
        ◆ EXCIT = _F (
             ◆ INTE_SPEC = interspectrum,
             ◇ NUME_VITE_FLUI = int,
             ◇ OPTION =/"TOUT" (by default),
                        /"DIAG ",
             ◇ MODAL =/"OUI ",
                       /"NON" (by default),
             # If: (not exists (" MODAL ")) or (equal_to (" MODAL ", 'NON'))
                 ◆/NUME_ORDRE_I = int,
                   /NOEUD_I = no,
                 # If: exists (" NUME_ORDRE_I ")
                     ◇/CHAM_NO = cham_no,
                       /NOEUD = no,
                     # If: exists (" NOEUD ")
                         ◆ NOM_CMP = text,
                     ◇ GRANDEUR =/"DEPL_R" (by default),
                                  /"EFFO ",
                                  /"SOUR_DEBI_VOLU ",
                                  /"SOUR_DEBI_MASS ",
                                  /"SOUR_PRESS ",
                                  /"SOUR_FORCE ",
                     ◇ DERIVATION =/0 (by default),
                                    /1,
                                    /2,
                 # If: exists (" NOEUD_I ")
                     ◆ NOM_CMP_I = text,
                     ◆ NOEUD = no,
                     ◆ NOM_CMP = text,
                     ◇ GRANDEUR =/"DEPL_R" (by default),
                                  /"EFFO ",
                                  /"SOUR_DEBI_VOLU ",
                                  /"SOUR_DEBI_MASS ",
                                  /"SOUR_PRESS ",
                                  /"SOUR_FORCE ",
                     ◇ DERIVATION =/0 (by default),
                                    /1,
                                    /2,
             # If: (equal_to (" MODAL ", 'OUI'))
                 ◆ NUME_ORDRE_I = int,
                 ◇ GRANDEUR =/"DEPL_R" (by default),
                              /"EFFO ",
                              /"SOUR_DEBI_VOLU ",
                              /"SOUR_DEBI_MASS ",
                              /"SOUR_PRESS ",
                              /"SOUR_FORCE ",
                 ◇ DERIVATION =/0 (by default),
                                /1,
                                /2,
          ),
        ◇ REPONSE = _F (
             ◇ DERIVATION =/0 (by default),
                            /1,
                            /2,
             ◇ OPTION =/"TOUT" (by default),
                        /"DIAG ",
             ◇ & FREQ_MIN = float,
               & FREQ_MAX = float,
             ◇ PAS = float,
             # If: not exists (" FREQ_MIN ")
                 ◇ FREQ_EXCIT =/"AVEC" (by default),
                                /"SANS ",
                 ◇ NB_POIN_MODE = int (default: 50),
          ),
        ◇ TITRE = text,
        ◇ INFO =/1 (by default),
                 /2,
    )
    
    ◆: mandatory
    ◇: optional
    : present by default
    &: together
    /: only one among
    |: several possible choices