cdef class reify: """Use as a class method decorator. It operates almost exactly like the Python `@property` decorator, but it puts the result of the method it decorates into the instance dict after the first call, effectively replacing the function it decorates with an instance variable. It is, in Python parlance, a data descriptor. """ cdef object wrapped cdef object name def __init__(self, wrapped): self.wrapped = wrapped self.name = wrapped.__name__ @property def __doc__(self): return self.wrapped.__doc__ def __get__(self, inst, owner): try: try: return inst._cache[self.name] except KeyError: val = self.wrapped(inst) inst._cache[self.name] = val return val except AttributeError: if inst is None: return self raise def __set__(self, inst, value): raise AttributeError("reified property is read-only")