Hi,
when declaring a C function in pure mode, you eventually end up with this:
@cython.cfunc
@cython.returns(cython.bint)
@cython.locals(a=cython.int, b=cython.int, c=cython.int)
def c_compare(a,b):
c = 5
return a == b + c
That is very verbose, making it hard to find the name of the actual
function. It's also not very intuitive that @cython.locals() is the way to
declare arguments.
I would find it more readable to support this:
@cython.cfunc(cython.bint, a=cython.int, b=cython.int)
@cython.locals(c=cython.int)
def c_compare(a,b):
c = 5
return a == b
But the problem here is that it conflicts with
@cython.cfunc
def c_compare(a,b):
c = 5
return a == b
when executed from Shadow.py. How should the fake decorator know that it is
being called with a type as first argument and not with the function it
decorates? Legacy, legacy ...
An alternative would be this:
@cython.cfunc(a=cython.int, b=cython.int, _returns=cython.bint)
@cython.locals(c=cython.int)
def c_compare(a,b):
c = 5
return a == b
But that's not clearer than an explicit decorator for the return value.
I'm somewhat concerned about the redundancy this introduces with @locals(),
which could still be used to declare argument types (even conflicting
ones). However, getting rid of the need for a separate @returns() seems
worthwhile by itself, so this might provide a compromise:
@cython.cfunc(returns=cython.bint)
@cython.locals(a=cython.int, b=cython.int, c=cython.int)
def c_compare(a,b):
c = 5
return a == b + c
This would work in Shadow.py because it's easy to distinguish between a
positional argument (the decorated function) and a keyword argument
("returns"). It might lead to bugs in user code, though, if they forget to
pass the return type as a keyword argument. Maybe just a minor concern,
because the decorator doesn't read well without the keyword.
What do you think? Is this worth doing something about at all?
Stefan
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