> >    @sorted = sort { $^a.foo('bar').compute <=> $^b.foo('bar').compute}
> >                 @unsorted;

> > Often the expressions on each side are even longer than that.  But one
> > thing remains:  both sides are exactly the same, substitute a $^b for
> > a $^a.

> The problem, then, isn't specific to sort; it happens any time that you
> find yourself needing to do the same things to multiple arguments.  As
> such, the solution ought to be more general than just sort.  

> You're looking for something to the effect of:

>   @sorted = sort { parameters($^a <=> $^b).foo('bar').compute }

> That is, you need a way to factor C<.foo('bar').compute> out from each
> of the arguments that it applies to.  For list arguments, this is
> straightforward: pipe the list arguments through a map before you pipe
> them into the routine.  A similar approach could be used with named
> arguments.  The problem comes when you deal with positional arguments.