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51 lines
1.4 KiB
51 lines
1.4 KiB
5 years ago
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# Hybrid methods/attributes, based on similar functionality in SQLAlchemy:
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# http://docs.sqlalchemy.org/en/improve_toc/orm/extensions/hybrid.html
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class hybrid_method(object):
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def __init__(self, func, expr=None):
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self.func = func
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self.expr = expr or func
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def __get__(self, instance, instance_type):
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if instance is None:
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return self.expr.__get__(instance_type, instance_type.__class__)
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return self.func.__get__(instance, instance_type)
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def expression(self, expr):
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self.expr = expr
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return self
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class hybrid_property(object):
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def __init__(self, fget, fset=None, fdel=None, expr=None):
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self.fget = fget
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self.fset = fset
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self.fdel = fdel
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self.expr = expr or fget
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def __get__(self, instance, instance_type):
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if instance is None:
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return self.expr(instance_type)
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return self.fget(instance)
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def __set__(self, instance, value):
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if self.fset is None:
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raise AttributeError('Cannot set attribute.')
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self.fset(instance, value)
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def __delete__(self, instance):
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if self.fdel is None:
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raise AttributeError('Cannot delete attribute.')
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self.fdel(instance)
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def setter(self, fset):
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self.fset = fset
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return self
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def deleter(self, fdel):
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self.fdel = fdel
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return self
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def expression(self, expr):
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self.expr = expr
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return self
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