Re: [stack] sweetening concatenative syntax

On Thu, Mar 6, 2008 at 6:12 PM, Stevan Apter <[email protected]> wrote:
> forget about the partial application case. what i want in my toolkit
> is a single combinator 'map' which takes an n-ary function and applies
> it to each of a list of length-n lists. not map1, map2, ... for each
> case. is that what's going on here? or does typing rule out having
> such a combinator?

It really has to do with how you structure your lists. In Cat this is
feasible if your list is a lists of functions.

define mapN { [apply] swap compose [quote] compose map }

[[1 2] [3 4] [5 6]] list [+] mapN => [[3][7][11]]
[[1] [2] [3] [4]] list [2 *] mapN => [[2][4][6][8]] //

Cat however has untyped lists, so there is some cheating going on at
the type-level, but this would be feasible with typed lists as well.

The only serious restriction here AFAICS is that your function has to
produce a single result even though it can consume n arguments.

- Christopher