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comparison python/ppci/c3/visitor.py @ 300:158068af716c

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yafm
author Windel Bouwman
date Tue, 03 Dec 2013 18:00:22 +0100
parents python/c3/visitor.py@a747a45dcd78
children b145f8e6050b
comparison
equal deleted inserted replaced
299:674789d9ff37 300:158068af716c
1 from .astnodes import *
2
3
4 class Visitor:
5 """
6 Visitor that can visit all nodes in the AST
7 and run pre and post functions.
8 """
9 def visit(self, node, f_pre=None, f_post=None):
10 self.f_pre = f_pre
11 self.f_post = f_post
12 self.do(node)
13
14 def do(self, node):
15 # Run visitor:
16 if self.f_pre:
17 self.f_pre(node)
18
19 # Descent into subnodes:
20 if type(node) is Package:
21 for decl in node.declarations:
22 self.do(decl)
23 elif type(node) is Function:
24 for s in node.declarations:
25 self.do(s)
26 self.do(node.body)
27 elif type(node) is CompoundStatement:
28 for s in node.statements:
29 self.do(s)
30 elif type(node) is IfStatement:
31 self.do(node.condition)
32 self.do(node.truestatement)
33 if node.falsestatement:
34 self.do(node.falsestatement)
35 elif type(node) is FunctionCall:
36 for arg in node.args:
37 self.do(arg)
38 elif type(node) is Assignment:
39 self.do(node.lval)
40 self.do(node.rval)
41 elif type(node) is ReturnStatement:
42 self.do(node.expr)
43 elif type(node) is Binop:
44 self.do(node.a)
45 self.do(node.b)
46 elif type(node) is Unop:
47 self.do(node.a)
48 elif type(node) is ExpressionStatement:
49 self.do(node.ex)
50 elif type(node) is TypeCast:
51 self.do(node.a)
52 elif type(node) is FieldRef:
53 self.do(node.base)
54 elif type(node) is Deref:
55 self.do(node.ptr)
56 elif type(node) is Constant:
57 self.do(node.value)
58 elif type(node) in [VariableUse, Variable, Literal, FunctionType,
59 DefinedType, FormalParameter, LocalVariable]:
60 # Those nodes do not have child nodes.
61 pass
62 elif type(node) is WhileStatement:
63 self.do(node.condition)
64 self.do(node.statement)
65 else:
66 raise Exception('Could not visit "{0}"'.format(node))
67
68 # run post function
69 if self.f_post:
70 self.f_post(node)
71
72
73 class AstPrinter:
74 """ Prints an AST as text """
75 def printAst(self, pkg):
76 self.indent = 0
77 visitor = Visitor()
78 visitor.visit(pkg, self.print1, self.print2)
79
80 def print1(self, node):
81 print(' ' * self.indent + str(node))
82 self.indent += 2
83
84 def print2(self, node):
85 self.indent -= 2