chipper.core

core.clj

(defn- arrow?
  "predicate that returns true if x is =>"
  [x]
  (and (symbol? x) (= (name x) "=>")))

(defn- split-body
  "splits expression into two parts, one with input
   pins and the other with => and outputs"
  [body]
  (split-with (complement arrow?) body))

(defn expand-defgate
  "recursively expands a gate with the right scoping"
  [forms outs]
  (if (empty? forms)
      outs
      (let [[[name & body] & rest] forms
            [[args] [_ & [outputs]]] (split-body body)]
        `(let [~(vec outputs) (~name ~@args)]
          ~(expand-defgate rest outs)))))

(defmacro defgate
  "defines a logical gate with a name, input/output
   pins, and a implementation consisting of other gates"
  [gate ins _ outs & forms]
  `(defn ~gate ~ins
         ~(expand-defgate forms outs)))