yacc_nodoc.py (4479:61d3ed46e373) yacc_nodoc.py (6498:e21e9ab5fad0)
1# -----------------------------------------------------------------------------
2# yacc_nodoc.py
3#
4# Rule with a missing doc-string
5# -----------------------------------------------------------------------------
6import sys
1# -----------------------------------------------------------------------------
2# yacc_nodoc.py
3#
4# Rule with a missing doc-string
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'),
18 ('right','UMINUS'),
19 )
20
21# dictionary of names
22names = { }
23
24def p_statement_assign(t):
25 'statement : NAME EQUALS expression'
26 names[t[1]] = t[3]
27
28def p_statement_expr(t):
9import ply.yacc as yacc
10
11from calclex import tokens
12
13# Parsing rules
14precedence = (
15 ('left','PLUS','MINUS'),
16 ('left','TIMES','DIVIDE'),
17 ('right','UMINUS'),
18 )
19
20# dictionary of names
21names = { }
22
23def p_statement_assign(t):
24 'statement : NAME EQUALS expression'
25 names[t[1]] = t[3]
26
27def p_statement_expr(t):
29 print t[1]
28 print(t[1])
30
31def p_expression_binop(t):
32 '''expression : expression PLUS expression
33 | expression MINUS expression
34 | expression TIMES expression
35 | expression DIVIDE expression'''
36 if t[2] == '+' : t[0] = t[1] + t[3]
37 elif t[2] == '-': t[0] = t[1] - t[3]
38 elif t[2] == '*': t[0] = t[1] * t[3]
29
30def p_expression_binop(t):
31 '''expression : expression PLUS expression
32 | expression MINUS expression
33 | expression TIMES expression
34 | expression DIVIDE expression'''
35 if 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]
39 elif t[3] == '/': t[0] = t[1] / t[3]
38 elif t[2] == '/': t[0] = t[1] / t[3]
40
41def p_expression_uminus(t):
42 'expression : MINUS expression %prec UMINUS'
43 t[0] = -t[2]
44
45def p_expression_group(t):
46 'expression : LPAREN expression RPAREN'
47 t[0] = t[2]
48
49def p_expression_number(t):
50 'expression : NUMBER'
51 t[0] = t[1]
52
53def p_expression_name(t):
54 'expression : NAME'
55 try:
56 t[0] = names[t[1]]
57 except LookupError:
39
40def p_expression_uminus(t):
41 'expression : MINUS expression %prec UMINUS'
42 t[0] = -t[2]
43
44def p_expression_group(t):
45 'expression : LPAREN expression RPAREN'
46 t[0] = t[2]
47
48def p_expression_number(t):
49 'expression : NUMBER'
50 t[0] = t[1]
51
52def p_expression_name(t):
53 'expression : NAME'
54 try:
55 t[0] = names[t[1]]
56 except LookupError:
58 print "Undefined name '%s'" % t[1]
57 print("Undefined name '%s'" % t[1])
59 t[0] = 0
60
61def p_error(t):
58 t[0] = 0
59
60def p_error(t):
62 print "Syntax error at '%s'" % t.value
61 print("Syntax error at '%s'" % t.value)
63
64yacc.yacc()
65
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68
62
63yacc.yacc()
64
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