マクロコンビネータ in infixing.clj

macro-combinator.clj

(use 'infixing.core)

(defn >>= [l f] (apply concat (map f l)))
(def mzero (list))
(defn return [x] (list x))

(def macro-combinator-rule
  (rules
    (infix-map    11 :=     (fn [x a] (fn [b] `(let [~x ~a] ~b))))
    (infix-map     0 :in    (fn [m a] (m a)))
    (infix-map     0 :where (fn [a m] (m a)))
    (infixr-space  2        (fn [m k] (fn [a] (m (k a)))))
    (infix-map     9 '<-    (fn [x a] (fn [b] `(>>= ~a (fn [~x] ~b)))))
    (infix-map     5 :when  (fn [m a] (fn [b] (m `(if ~a ~b mzero)))))
    (infix-map     0 '|     (fn [a m] (m `(return ~a))))))

(defmacro macro-combinator [code]
  (infixing macro-combinator-rule code))

(println (macroexpand '(macro-combinator (x := 1, y := 2 :in (list x y)))))
(println (macroexpand '(macro-combinator (x | x <- '(1 2 3)))))
(println (macroexpand '(macro-combinator ((list x y) | x <- '(1 2 3) y <- (range (inc x) 5)))))
(println (macroexpand '(macro-combinator ((list x y) | x <- (range 1 5) :when (even? x)
                                                       y <- (range (inc x) 5) :when (odd? y)))))

(println (macro-combinator (x := 1, y := 2 :in (list x y))))
(println (macro-combinator (x | x <- '(1 2 3))))
(println (macro-combinator ((list x y) | x <- '(1 2 3) y <- (range (inc x) 5))))
(println (macro-combinator ((list x y) | x <- (range 1 5) :when (even? x)
                                         y <- (range (inc x) 5) :when (odd? y))))