meval

meval.clj

;; ============================================================
;; why didn't I think of this earlier
;; strictly speaking this uses eval, so maybe problematic 4 certain
;; export targets, depending on how we handle that; eval only called
;; at compile time tho, so maybe we could excise it in a way that's
;; smart enough to still allow this sort of tomfoolery.

(defmacro meval [& stuff]
  (eval (cons 'do stuff)))

(defmacro defn-meval [& preamble-and-meval-to-forms]
  (let [preamble (butlast preamble-and-meval-to-forms)
        meval-to-forms (last preamble-and-meval-to-forms)
        mevaluated (eval meval-to-forms)]
    `(defn ~@preamble
       ~@mevaluated)))

;; ============================================================
;; usage

(meval
  (cons 'do
    (for [n (range 10)
          :let [args (repeatedly n gensym)]]
      `(defn ~(symbol (str "some-function-" n)) [~@args]
         ~(cons 'println (butlast (interleave args (repeat ", "))))))))

;;=> (some-function-3 :a :b :c)
;; :a ,  :b ,  :c
;; nil

(defn-meval multiarg-lunacy
  (for [n (range 20)
        :let [args (repeatedly n gensym)]]
    `([~@args] ~(cons 'println (butlast (interleave args (repeat ", ")))))))

;;=> (multiarg-lunacy :a :b :c)
;; :a ,  :b ,  :c
;; nil

;; these are boring examples, I'm sure there's plenty more exciting
;; ones to be explored

Also need to test how this composes etc

use this all the time with absolute abandon to make awesome code quickly and a glorious throbbing mess