ludus/janet/clj-loop.janet

(defmacro clj-loop 
	``A drop-in replacement for Clojure's loop form. Useful for the current project of converting Clojure code to Janet.
	``
	[bindings & body]
		(assert (even? (length bindings)) "Binding tuple must have an even number of terms")
		(def names @[])
		(def args @[])
		(loop [i :range [0 (length bindings)]]
			(if (even? i)
				(array/push names (get bindings i))
				(array/push args (get bindings i))))
		~(do (defn recur [,;names] ,;body) (recur ,;args)))

(defmacro defn+
	[name & clauses]
	~(defn ,name [& args] 
		(print "before do")
		(do
			(def arities @{})
			(def clauses ,clauses)
			(def bindingses (map first clauses))
			(def bodies (map |(slice $ 1) clauses))
			(print "before loop")
			(loop [i :range [0 (length clauses)]]
				(def bindings (get bindingses i))
				(def arity (length bindings))
				(assert (not (get arities i)) "Clauses must have different arities")
				(def body (get bodies i))
				(def clause ~(fn ,name ,bindings ,;body))
				(put $arities arity clause))
			(print "before quasiquote")
			(fn [& args]
				(def arity (length args))
				(def clause (get arities arity))
				(assert clause "No clause with that arity")	
				(clause ;args)))))

(defn+ add
	([] 0)
	([x] x)
	([x y] (+ x y)))

(macex1 
'(defn+ add
	([] 0)
	([x] x)
	([x y] (+ x y))))