= Flexible Partial Application =

Are there any subtle reasons for why something like the following
couldn't be allowed?

{{{
> foo x y z w = ...
> bar x w = foo x _ _ w
}}}

I.e. a more flexible version of partial application. This would be
translated to

{{{
> bar x w = \y z -> foo x y z w
}}}

I.e a function which takes the "_" parameters in the same order they
were encountered in the function application.

== Related proposals ==

 * feature request for ghc at [http://hackage.haskell.org/trac/ghc/ticket/315 this ticket]
 * conflicts with MagicUnderscore

== Pros ==

== Cons ==

One can usually assume '''id e = e''', for any '''e''', but

    {{{
    id (f _ x) y  ===  id (\y->f y x) y === f y x
    /=
    f _ x y === \z -> f z x y
    }}}

Or would '''(f _ x) y''' and '''f _ x y''' maybe be different? That would fix the problem above, while introducing another.