comparison ply-3.8/test/yacc_notfunc.py @ 7267:343ff337a19b

<ais523> ` tar -xf ply-3.8.tar.gz
author HackBot
date Wed, 23 Mar 2016 02:40:16 +0000
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7266:61a39a120dee 7267:343ff337a19b
1 # -----------------------------------------------------------------------------
2 # yacc_notfunc.py
3 #
4 # p_rule not defined as a function
5 # -----------------------------------------------------------------------------
6 import sys
7
8 if ".." not in sys.path: sys.path.insert(0,"..")
9 import ply.yacc as yacc
10
11 from calclex import tokens
12
13 # Parsing rules
14 precedence = (
15 ('left','PLUS','MINUS'),
16 ('left','TIMES','DIVIDE'),
17 ('right','UMINUS'),
18 )
19
20 # dictionary of names
21 names = { }
22
23 p_statement_assign = "Blah"
24
25 def p_statement_expr(t):
26 'statement : expression'
27 print(t[1])
28
29 def p_expression_binop(t):
30 '''expression : expression PLUS expression
31 | expression MINUS expression
32 | expression TIMES expression
33 | expression DIVIDE expression'''
34 if t[2] == '+' : t[0] = t[1] + t[3]
35 elif t[2] == '-': t[0] = t[1] - t[3]
36 elif t[2] == '*': t[0] = t[1] * t[3]
37 elif t[2] == '/': t[0] = t[1] / t[3]
38
39 def p_expression_uminus(t):
40 'expression : MINUS expression %prec UMINUS'
41 t[0] = -t[2]
42
43 def p_expression_group(t):
44 'expression : LPAREN expression RPAREN'
45 t[0] = t[2]
46
47 def p_expression_number(t):
48 'expression : NUMBER'
49 t[0] = t[1]
50
51 def p_expression_name(t):
52 'expression : NAME'
53 try:
54 t[0] = names[t[1]]
55 except LookupError:
56 print("Undefined name '%s'" % t[1])
57 t[0] = 0
58
59 def p_error(t):
60 print("Syntax error at '%s'" % t.value)
61
62 yacc.yacc()
63
64
65
66