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from py.__.magic.viewtype import View
def test_class_dispatch():
### Use a custom class hierarchy with existing instances
class Picklable(View):
pass
class Simple(Picklable):
__view__ = object
def pickle(self):
return repr(self.__obj__)
class Seq(Picklable):
__view__ = list, tuple, dict
def pickle(self):
return ';'.join([Picklable(item).pickle() for item in self.__obj__])
class Dict(Seq):
__view__ = dict
def pickle(self):
return Seq.pickle(self) + '!' + Seq(self.values()).pickle()
assert Picklable(123).pickle() == '123'
assert Picklable([1,[2,3],4]).pickle() == '1;2;3;4'
assert Picklable({1:2}).pickle() == '1!2'
def test_custom_class_hierarchy():
### Use a custom class hierarchy based on attributes of existing instances
class Operation:
"Existing class that I don't want to change."
def __init__(self, opname, *args):
self.opname = opname
self.args = args
existing = [Operation('+', 4, 5),
Operation('getitem', '', 'join'),
Operation('setattr', 'x', 'y', 3),
Operation('-', 12, 1)]
class PyOp(View):
def __viewkey__(self):
return self.opname
def generate(self):
return '%s(%s)' % (self.opname, ', '.join(map(repr, self.args)))
class PyBinaryOp(PyOp):
__view__ = ('+', '-', '*', '/')
def generate(self):
return '%s %s %s' % (self.args[0], self.opname, self.args[1])
codelines = [PyOp(op).generate() for op in existing]
assert codelines == ["4 + 5", "getitem('', 'join')", "setattr('x', 'y', 3)", "12 - 1"]
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