2. Syntax

evol_char = LIRE_PLEXUS (
    ◇ UNITE = unit (default: 19),
    ◇ FORMAT = "IDEAS ",
    ◆ MAIL_PLEXUS = mesh,
    ◆ MAILLAGE = mesh,
    ◆ MODELE = model,
    ◆/TOUT_ORDRE = "OUI" (or not specified),
      /NUME_ORDRE = int,
      /INST = float,
      /LIST_INST = listr8,
      /LIST_ORDRE = listis,
    # If: exists (" LIST_INST ") or exists (" INST ")
        ◇ CRITERE =/"RELATIF" (by default),
                    /"ABSOLU ",
        # If: (equal_to (" CRITERE ", 'RELATIF'))
            ◇ PRECISION = float (default: 1e-06),
        # If: (equal_to (" CRITERE ", 'ABSOLU'))
            ◆ PRECISION = float,
    ◇ TITRE = text,
)

◆: mandatory
◇: optional
: present by default
&: together
/: only one among
|: several possible choices