simple propagator-backed spreadsheet -- see http://gitweb.adaptive.cs.unm.edu/propagator.git

spreadsheet.clj

(ns propagator.spreadsheet ; see http://gitweb.adaptive.cs.unm.edu/propagator.git
  (use propagator))

(def xrange 10) (def yrange 10)

(def spreadsheet
  (map (fn [_] (map (fn [_]
                     (let [c (gensym)] (eval `(defcell ~c nil)) c))
                   (range xrange)))
       (range yrange)))

(defn spreadsheet-print []
  (doseq [row spreadsheet]
    (->> (map (comp deref eval) row)
         (map #(if (nil? %) "[     ]" (format "[%5.2f]" (float %))))
         (interpose " ")
         (apply str)
         (println))) (println))

(defn parse [exp]
  (let [refs (transient [])]
    (letfn [(parse [exp]
                   (cond
                    (vector? exp)
                    (let [[x y] exp
                          c (-> spreadsheet (nth x) (nth y))]
                      (conj! refs c) c)
                    (seq? exp)
                    (let [lst (map parse exp)] (dorun lst) lst)
                    true exp))]
      [(parse exp) (set (persistent! refs))])))

(defn spreadsheet-set [[x y] v]
  (if (seq? v)
    (let [[e rs] (parse v)
          out-cell (-> spreadsheet (nth y) (nth x))]
      (eval `(defpropagator fm ~(vec rs) [~out-cell] ~e)))
    (set-cell (eval (-> spreadsheet (nth y) (nth x))) v)))

(comment                                   ; example usage
  (spreadsheet-set [2 2] '(+ [1 1] [0 0])) ; a formula -- propagator
  (spreadsheet-set [0 0] 2)                ; an integer -- cell
  (spreadsheet-set [1 1] 45)               ; an integer -- cell
  (spreadsheet-print))