Commit bcaa897
Sakis Kasampalis
visitor to python3
1 parent 00028ad commit bcaa897
1 file changed
Lines changed: 26 additions & 30 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -1,38 +1,34 @@ | |||
| 1 | 1 | '''http://peter-hoffmann.com/2010/extrinsic-visitor-pattern-python-inheritance.html''' | |
| 2 | 2 | ||
| 3 | - class Node(object): | ||
| 4 | - pass | ||
| 5 | - class A(Node): | ||
| 6 | - pass | ||
| 7 | - class B(Node): | ||
| 8 | - pass | ||
| 9 | - class C(A,B): | ||
| 10 | - pass | ||
| 3 | + class Node(object): pass | ||
| 4 | + class A(Node): pass | ||
| 5 | + class B(Node): pass | ||
| 6 | + class C(A,B): pass | ||
| 11 | 7 | ||
| 12 | - class Visitor(object): | ||
| 13 | - def visit(self, node, *args, **kwargs): | ||
| 14 | - meth = None | ||
| 15 | - for cls in node.__class__.__mro__: | ||
| 16 | - meth_name = 'visit_'+cls.__name__ | ||
| 17 | - meth = getattr(self, meth_name, None) | ||
| 8 | + class Visitor(object): | ||
| 9 | + def visit(self, node, *args, **kwargs): | ||
| 10 | + meth = None | ||
| 11 | + for cls in node.__class__.__mro__: | ||
| 12 | + meth_name = 'visit_'+cls.__name__ | ||
| 13 | + meth = getattr(self, meth_name, None) | ||
| 14 | + if meth: | ||
| 15 | + break | ||
| 18 | 16 | ||
| 19 | - if meth: | ||
| 20 | - break | ||
| 17 | + if not meth: | ||
| 18 | + meth = self.generic_visit | ||
| 19 | + return meth(node, *args, **kwargs) | ||
| 21 | 20 | ||
| 22 | - meth = self.generic_visit | ||
| 23 | - return meth(node, *args, **kwargs) | ||
| 21 | + def generic_visit(self, node, *args, **kwargs): | ||
| 22 | + print('generic_visit '+node.__class__.__name__) | ||
| 24 | 23 | ||
| 25 | - def visit_B(self, node, *args, **kwargs): | ||
| 26 | - print 'visit_B '+node.__class__.__name__ | ||
| 24 | + def visit_B(self, node, *args, **kwargs): | ||
| 25 | + print('visit_B '+node.__class__.__name__) | ||
| 27 | 26 | ||
| 28 | - def generic_visit(self, node, *args, **kwargs): | ||
| 29 | - print 'generic_visit '+node.__class__.__name__ | ||
| 30 | 27 | ||
| 31 | - if __name__ == '__main__': | ||
| 32 | - a = A() | ||
| 33 | - b = B() | ||
| 34 | - # c = C() | ||
| 35 | - visitor = Visitor() | ||
| 36 | - visitor.visit(a) | ||
| 37 | - visitor.visit(b) | ||
| 38 | - # visitor.visit(c) | ||
| 28 | + a = A() | ||
| 29 | + b = B() | ||
| 30 | + c = C() | ||
| 31 | + visitor = Visitor() | ||
| 32 | + visitor.visit(a) | ||
| 33 | + visitor.visit(b) | ||
| 34 | + visitor.visit(c) | ||
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