[Python-ideas] An easier syntax for writing decorators (&similar things)?

[Aaron Brady]

> >>>> When writing decorators especially when it's one that needs
> >>>> arguments
> >>>> other than the function to be wrapped, it often gets rather ugly...
> >> [...]
> >>> Whhy not create a (meta-)decorator to do this? Something like:
> >> [...]
> >
> > Following up post from 10/8/07.
> >
> >> To follow up on my untested suggestion, here's one that is tested:
> >>
> >> # This metadecorator hasn't changed
> >>
> >> def decorator_withargs(decf):
> >>    def decorator(*args, **kwargs):
> >>        def decorated(f):
> >>            return decf(f, *args, **kwargs)
> >>        return decorated
> >>    return decorator
> >
> > This is equivalent to:
> > (1)
> >     decorator_withargs= partial( partial, prepartial )
> 
> [where partial is as in functools and
> prepartial(f, x, y)(z, t) <=> f(z, t, x, y)]
> 
> Indeed, and if one restricts decorator_withargs to keyword arguments,
> one can simply define it as:
> 
> decorator_withargs = partial(partial, partial)

I believe you can put -f- in the last pos'l argument and have this work.

def mydec( arg0, arg1, f, before='entering %s', after='%s returns %%s').

> Which is the curry operator!  So decorator_withargs is some sort of
> curry. In fact I had never realised before that this was a way to
> define curry (for functions with 2 arguments)
> 
> curry = partial(partial, partial)
> 
> [if f is a two-arguments function then curry(f)(x)(y) is f(x, y)]
> 
> This means that a meta-decorator (i.e. a decorator for decorators) is
> a kind of currying operator.
> 
> > Intriguing.
> 
> !