- """expression : expression OR_OP expression"""
- p[0] = ('OR', p[1], p[3])
+ """expression : expression SP0 OR_OP SP0 expression"""
+ p[0] = ('OR', p[1], p[5])
+
+def p_expression_in_parens(p):
+ """expression : expression_parens"""
+ p[0] = p[1]
+
+def p_l_expression(p):
+ """l_expression : expression_parens
+ | expression SP1
+ """
+ if len(p) == 2:
+ p[0] = p[1]
+ elif len(p) == 3:
+ p[0] = p[1]
+ else:
+ raise ValueError(p)
+
+def p_r_expression(p):
+ """r_expression : expression_parens
+ | SP1 expression
+ """
+ if len(p) == 2:
+ p[0] = p[1]
+ elif len(p) == 3:
+ p[0] = p[2]
+ else:
+ raise ValueError(p)