defunits.clj

;; WIP...

(defn quote-units
  [units]
  (let [syms (filter symbol? units)
        vals (filter number? units)]
    (interleave (map (fn [u] `'~u) syms) vals)))

(defmacro defunits
  [quantity base-unit & units]
  `(defmacro ~(symbol (str "unit-of-" quantity))
     [val# un#]
     (* val# (case un# ~@(quote-units units)))))

;; above should create this...

(defmacro unit-of-time
  [value unit]
  `(* ~value
      ~(case unit
         s 1
         m 60
         h 3600
         d 86400
         ms 1/1000
         us 1/1000000)))

;; Goal
(defunits time s
  m 60
  h 3600
  d 86400
  ms 1/1000
  us 1/100000)

;; sample test
(unit-of-time 1 d)
;; => 86400