ski.carp

; the SKI combinator calculus in carp
;
; SKI is a calculus of three constructions:
; - `s`, which takes two functions and an argument,
;   applying the second function to the argument and
;   passing the result into the first function along
;   with the original argument,
; - `k`, which takes two arguments and returns the
;   first,
; - and `i`, which takes one argument and returns it
;   as is—the identity function.
;
; while it might not be immediately obvious how this
; is useful at all, it’s actually quite powerful when
; combined with such things as church encodings.
;
; for a simple example, let’s consider doubling a
; number:
;   (s + i 10)
; which will run the identity function on `10`, which
; will result in `10` being passed to `s` twice.
;

; the SKI module, containing the combinators.
; the combinators themselves should be relatively
; obvious from the description above.
(defmodule SKI
  (defn s [f g x] (f x (g x)))
  (defn k [x y] x)
  (defn i [x] x)
)