Tuple parameter unpacking in 3.x

[Duncan Booth]

Martin Geisler <mg at daimi.au.dk> wrote:

> Letting the callbacks take several arguments would definitely be the
> nicest syntax, but I'm unfortunately restricted by the Twisted
> framework: there all functions in a callback chain return one result
> which is passed to the next callback as the first argument. That is why
> I do a fair amount of tuple unpacking in my code.
 
If you only have to contend with that one pattern then you could write a 
decorator to unpack a single argument. Maybe not ideal, but then you have 
the option to write:

@unpacked
def product(a, b):
    return a*b
ci.addCallback(product)

or

ci.addCallback(unpacked(lambda a,b: a*b))

for some suitable definition of unpacked.