On Wed, Jan 27, 2016 at 2:06 AM, Paul Moore <p.f.moore@gmail.com> wrote:
Well, classes can be callable already, so how about
@DBC class myfunction: def __call__(self, args): ... @precondition def requires(self): ... @postcondition def ensures(self, result): ...
The DBC class decorator does something like
def DBC(cls): def wrapper(*args, **kw): fn = cls() fn.args = args fn.kw = kw for pre in fn.__preconditions__: pre() result = fn(*args, **kw) for post in fn.__postconditions__: post(result) return wrapper
Pre and post conditions can access the args via self.args and self.kw. The method decorators would let you have multiple pre- and post-conditions. Or you could use "magic" names and omit the decorators.
I'd rather use magic names - something like: @DBC class myfunction: def body(self, args): ... def requires(self): ... def ensures(self, result): ... and then the DBC decorator can create a __call__ method. This still has one nasty problem though: the requires and ensures functions can't see function arguments. You could get around this by duplicating the argument list onto the other two, but who wants to do that? ChrisA