3 from ply import lex, yacc
7 tokens = ('NAME', 'AND_OP', 'OR_OP', 'NOT_OP')
9 t_NAME = '[a-z][a-z0-9_]*'
20 """Avoid warnings on stderr"""
24 def p_expression_name(p):
25 """expression : NAME"""
28 def p_expression_and_and(p):
29 """expression : expression AND_OP AND_OP expression"""
30 p[0] = ('AND', p[1], p[4])
32 def p_expression_and(p):
33 """expression : expression AND_OP expression"""
34 p[0] = ('AND', p[1], p[3])
36 def p_expression_not(p):
37 """expression : NOT_OP expression"""
40 def p_expression_or_or(p):
41 """expression : expression OR_OP OR_OP expression"""
42 p[0] = ('OR', p[1], p[4])
44 def p_expression_or(p):
45 """expression : expression OR_OP expression"""
46 p[0] = ('OR', p[1], p[3])
48 def p_expression_parens(p):
49 """expression : '(' expression ')'"""
50 p[0] = ('PARENS', p[2])
53 """Avoid warnings on stderr"""