Self Realizing code! Code that, when given a `what-i-want` and a vector of operators and operands, will create the lisp code to compute that result.

selfrealizing.clj

(ns self-realizing.core
  (:gen-class)
  (:require [clojure.math.combinatorics :as combo]))

(defmacro ignore-errors
  "Returns the result of evaluating e, or nil if it throws an exception."
  [e]
  `(try ~e (catch java.lang.Exception _# nil)))

(defn findr
  [what-i-want fn-domain]
  (for [sub (combo/subsets fn-domain)
        :when (ifn? (first sub))
        perm (combo/permutations sub)
        :when (= what-i-want (ignore-errors (eval perm)))]
    perm))

(comment
  (findr 3 ['+ 1 2 3])
  )

(comment
  (take 1 (findr 24 ['+ '* 1 2 3 4 5 6 7 8]))
  )

(comment
  (take 1 (findr "hello world!" ['+ '* 'str 1 2 3 "hello" " " "world" "!"]))
)