def p_constant_def(t):
    """constant_def : CONST ID EQUALS constant SEMI"""
    global name_dict
    id = t[2]
    value = t[4]
    lineno = t.lineno(1)
    if id_unique(id, 'constant', lineno):
        name_dict[id] = const_info(id, value, lineno)
constant_def : CONST ID EQUALS constant SEMI