Brett Cannon wrote:
> The second question is whether it is worth providing a function that
> will either figure out if a tuple and dict representing arguments
> would work in calling the function. Some have even suggested a
> function that returns the actual bindings if the call were to occur.
> Personally I don't see a huge use for either, but even less for the
> latter version. If people have a legit use case for either please
> speak up, otherwise I am tempted to keep the object simple.
One use case that comes to mind is a type-checking decorator (or
precondition-checking decorator, etc):
@precondition(lambda x,y: x>y)
@precondition(lambda y,z: y>z)
def foo(x, y, z): ...
where precondition is something like:
def precondition(test):
def add_precondition(func):
def f(*args, **kwargs):
bindings = func.__signature__.bindings(args, kwargs)
if not test(**bindings):
raise ValueError, 'Precontition not met'
func(*args, **kwargs)
return f
return add_precondition
-Edward
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