awesome threading macro. needs clojure.walk to work properly.

threadingmacro.clj

@@ -0,0 +1,39 @@
+;; robbed with thanks off of:
+;; http://bryangilbert.com/code/2013/07/30/anatomy-of-a-clojure-macro/
+
+(defn replace-if-underscore [element val] 
+  (if (= element '_) val element))
+
+(defn replace-underscores [form val]
+      (map #(replace-if-underscore % val) form))
+
+(defn convert-forms [val [next-form & other-forms]]               
+      (if (nil? next-form)                                         
+        val                                                           
+        (let [next-val (gensym)]                                   
+          `(let [~next-val ~(replace-underscores next-form val)]   
+             ~(convert-forms next-val other-forms)))))  
+
+(defmacro ->>> [init & forms]
+      (convert-forms init forms))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(->>> 20 
+      (* _ _ _)
+      (* _ _ _)) ;-> 512000000000
+
+(reduce * (repeat 9 20 )) ;-> 512000000000
+
+
+(->>> #{}
+      (conj _ 'doom)
+      (conj _ 'horror)
+      (_ 'treason)) ;-> nil
+
+(->>> #{}
+      (conj _ 'doom)
+      (conj _ 'horror)
+      (_ 'horror)) ;-> horror
+
+;; Awesome. Votes for this in the standard library!