[Python-ideas] PEP-3150

[Arnaud Delobelle]

On 14 Apr 2011, at 12:47, Carl M. Johnson wrote:

> On Wed, Apr 13, 2011 at 10:06 PM, Greg Ewing
> <greg.ewing at canterbury.ac.nz> wrote:
> 
>> In this particular case (i.e. a function that does nothing
>> but define and return another function) I'd like to be able
>> to write
>> 
>> def decorator(f)(*args, **kwargs):
>>   do something...
>> 
>> but that's a subject for another hotly-debated PEP!
> 
> Interesting, but could that be extended to support making a throwaway
> key function for sorted? With given it's obviously
> 
> sorted_list = sorted(original_list, key=keyfunc) given:
>   def keyfunc(item):
>       item = item.replace(" ", "")
>       item = item.lowercase()
>       ...
>       return item
> 
> but I can't see how that your proposal could be expanded beyond the
> one use case of decorator making, and today it's already possible to
> make a simple decorator decorator that injects f as the first arg:
> 
> class MetaDec:
>   def __init__(self, dec):
>       self.dec = dec
> 
>   def __call__(self, f):
>       def callme(*args, **kwargs):
>            return self.dec(f, *args, **kwargs)
>       return callme

You could spell that:

from functools import partial
def MetaDec(f):
    return partial(partial, f)

And this is just the curry function!

-- 
Arnaud