On Apr 20 2015, Harry Percival <hj...@cantab.net> wrote:
> My first reaction to type hints was "yuck", and I'm sure I'm not the only
> one to think that. viz (from some pycon slides):
>
> def zipmap(f: Callable[[int, int], int], xx: List[int],
> yy: List[int]) -> List[Tuple[int, int, int]]:
>
> arg. and imagine it with default arguments.
This is indeed ugly as hell and I certainly would not want to see this
in any Python file I'm working with.
However, I always assumed that whatever tools consume these annotations
are expected to be good enough at automatic type inference that
something like this would never be necessary?
In practice, I would hope that the above simplifies to
def zipmap(f, xx: List[int], yy: List[int]):
because (just picking a probably buggy random implementation)
zz = [] # --> z must be List[A]
for i in range(min(len(xx), len(yy))):
x = xx[i] # --> x must be int
y = xx[i] # --> y must be int
z = f(x,y) # --> f must be Callable[(int,int], B]
zz[i] = (x,y,z) # --> A must be Tuple[int,int,B]
return zz # --> return value must be List[Tuple[int,int,B]]
it doesn't catch that B = int, but I think that's acceptable.
Is this not the case? Are we really expecting people to write stuff like
the above?
Best,
-Nikolaus
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