Mercurial > repo

comparison ply-3.8/test/yacc_error7.py @ 7267:343ff337a19b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
<ais523> ` tar -xf ply-3.8.tar.gz
author HackBot
date Wed, 23 Mar 2016 02:40:16 +0000
parents
children
comparison
equal deleted inserted replaced
7266:61a39a120dee 7267:343ff337a19b
1 # -----------------------------------------------------------------------------
2 # yacc_error7.py
3 #
4 # Panic mode recovery test using deprecated functionality
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 def p_statements(t):
21 'statements : statements statement'
22 pass
23
24 def p_statements_1(t):
25 'statements : statement'
26 pass
27
28 def p_statement_assign(p):
29 'statement : LPAREN NAME EQUALS expression RPAREN'
30 print("%s=%s" % (p[2],p[4]))
31
32 def p_statement_expr(t):
33 'statement : LPAREN expression RPAREN'
34 print(t[1])
35
36 def p_expression_binop(t):
37 '''expression : expression PLUS expression
38 | expression MINUS expression
39 | expression TIMES expression
40 | expression DIVIDE expression'''
41 if t[2] == '+' : t[0] = t[1] + t[3]
42 elif t[2] == '-': t[0] = t[1] - t[3]
43 elif t[2] == '*': t[0] = t[1] * t[3]
44 elif t[2] == '/': t[0] = t[1] / t[3]
45
46 def p_expression_uminus(t):
47 'expression : MINUS expression %prec UMINUS'
48 t[0] = -t[2]
49
50 def p_expression_number(t):
51 'expression : NUMBER'
52 t[0] = t[1]
53
54 def p_error(p):
55 if p:
56 print("Line %d: Syntax error at '%s'" % (p.lineno, p.value))
57 # Scan ahead looking for a name token
58 while True:
59 tok = yacc.token()
60 if not tok or tok.type == 'RPAREN':
61 break
62 if tok:
63 yacc.restart()
64 return None
65
66 parser = yacc.yacc()
67 import calclex
68 calclex.lexer.lineno=1
69
70 parser.parse("""
71 (a = 3 + 4)
72 (b = 4 + * 5 - 6 + *)
73 (c = 10 + 11)
74 """)
75
76
77
78
79
80