This useless hack allows normal functions to be attached to a 'ThunkSpace' which causes the function to be lazily evaluated when the thunk is referenced. It is just a experiment using closures and descriptors to try and change python function call syntax.
Python, 39 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | class ThunkSpace(object):
"""
A ThunkSpace for Python. Assigning functions to an instance of ThunkSpace
will turn the function into a lazily evaluated attribute.
"""
def __setattr__(self, name, func):
def delete(self):
delattr(self.__class__, name)
def get(self):
return func()
def set(self, new_func):
def get(self):
return new_func()
setattr(self.__class__, name, property(get, set, delete))
setattr(self.__class__, name, property(get, set, delete))
if __name__ == "__main__":
def lazy_something():
return "lazy_something was called."
def lazy_something_else():
return "lazy_something_else was called."
#create a ThunkSpace
ts = ThunkSpace()
#create an attribute named lazy_func, which when referenced, will call
#lazy_something
ts.lazy_func = lazy_something
print ts.lazy_func
#the lazy_func attribute can be replaced with another function...
ts.lazy_func = lazy_something_else
print ts.lazy_func
|
You probably never want to use this recipe. :-)
Tags: programs
