yacc_rr.py (4479:61d3ed46e373) yacc_rr.py (6498:e21e9ab5fad0)
1# -----------------------------------------------------------------------------
2# yacc_rr.py
3#
4# A grammar with a reduce/reduce conflict
5# -----------------------------------------------------------------------------
6import sys
1# -----------------------------------------------------------------------------
2# yacc_rr.py
3#
4# A grammar with a reduce/reduce conflict
5# -----------------------------------------------------------------------------
6import sys
7sys.tracebacklimit = 0
8
7
9sys.path.insert(0,"..")
8if ".." not in sys.path: sys.path.insert(0,"..")
10import ply.yacc as yacc
11
12from calclex import tokens
13
14# Parsing rules
15precedence = (
16 ('left','PLUS','MINUS'),
17 ('left','TIMES','DIVIDE'),

--- 8 unchanged lines hidden (view full) ---

26 names[t[1]] = t[3]
27
28def p_statement_assign_2(t):
29 'statement : NAME EQUALS NUMBER'
30 names[t[1]] = t[3]
31
32def p_statement_expr(t):
33 'statement : expression'
9import ply.yacc as yacc
10
11from calclex import tokens
12
13# Parsing rules
14precedence = (
15 ('left','PLUS','MINUS'),
16 ('left','TIMES','DIVIDE'),

--- 8 unchanged lines hidden (view full) ---

25 names[t[1]] = t[3]
26
27def p_statement_assign_2(t):
28 'statement : NAME EQUALS NUMBER'
29 names[t[1]] = t[3]
30
31def p_statement_expr(t):
32 'statement : expression'
34 print t[1]
33 print(t[1])
35
36def 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]
34
35def p_expression_binop(t):
36 '''expression : expression PLUS expression
37 | expression MINUS expression
38 | expression TIMES expression
39 | expression DIVIDE expression'''
40 if t[2] == '+' : t[0] = t[1] + t[3]
41 elif t[2] == '-': t[0] = t[1] - t[3]
42 elif t[2] == '*': t[0] = t[1] * t[3]
44 elif t[3] == '/': t[0] = t[1] / t[3]
43 elif t[2] == '/': t[0] = t[1] / t[3]
45
46def p_expression_uminus(t):
47 'expression : MINUS expression %prec UMINUS'
48 t[0] = -t[2]
49
50def p_expression_group(t):
51 'expression : LPAREN expression RPAREN'
52 t[0] = t[2]
53
54def p_expression_number(t):
55 'expression : NUMBER'
56 t[0] = t[1]
57
58def p_expression_name(t):
59 'expression : NAME'
60 try:
61 t[0] = names[t[1]]
62 except LookupError:
44
45def p_expression_uminus(t):
46 'expression : MINUS expression %prec UMINUS'
47 t[0] = -t[2]
48
49def p_expression_group(t):
50 'expression : LPAREN expression RPAREN'
51 t[0] = t[2]
52
53def p_expression_number(t):
54 'expression : NUMBER'
55 t[0] = t[1]
56
57def p_expression_name(t):
58 'expression : NAME'
59 try:
60 t[0] = names[t[1]]
61 except LookupError:
63 print "Undefined name '%s'" % t[1]
62 print("Undefined name '%s'" % t[1])
64 t[0] = 0
65
66def p_error(t):
63 t[0] = 0
64
65def p_error(t):
67 print "Syntax error at '%s'" % t.value
66 print("Syntax error at '%s'" % t.value)
68
69yacc.yacc()
70
71
72
73
67
68yacc.yacc()
69
70
71
72