From 17c7eff5b8e876ac8f9f972aaa24a239faec62ad Mon Sep 17 00:00:00 2001
From: Eric Schulte <schulte.eric@gmail.com>
Date: Fri, 16 Apr 2010 22:47:06 -0600
Subject: [PATCH] adding ability to remember and graph structure of propagators

---
 propagator.org | 40 +++++++++++++++++++++++++++++++---------
 1 file changed, 31 insertions(+), 9 deletions(-)

diff --git a/propagator.org b/propagator.org
index de22092..08bafc2 100644
--- a/propagator.org
+++ b/propagator.org
@@ -18,9 +18,19 @@
     [name state]
     `(def ~name (agent ~state)))
   
+  (def prop-graph {})
+  
+  (defmacro remember-prop [name in-cells out-cells]
+    `(def prop-graph
+          (assoc prop-graph
+            (quote ~name)
+            {:in-cells (map (fn [x#] (name x#)) (quote ~in-cells))
+             :out-cells (map (fn [x#] (name x#)) (quote ~out-cells))})))
+  
   (defmacro propagator "Define a new propagator."
     [name in-cells out-cells & body]
     `(do
+       (remember-prop ~name ~in-cells ~out-cells)
        (defn ~(with-meta name
                 (assoc (meta name)
                   :in-cells in-cells :out-cells out-cells))
@@ -50,6 +60,7 @@
 #+end_src
 * extensions
 ** graphs of the propagator network
+draw a graph in a JFrame
 #+begin_src clojure
   (use 'vijual)
   (import '(javax.swing JFrame JPanel)
@@ -71,21 +82,32 @@
       (doto frame (.add panel) .pack (.setSize (+ offset width) (+ offset height)).show)))
 #+end_src
 
+pull a graph from a the propagators saved in the =prop-graph= variable
+#+begin_src clojure
+  (defn graph-propagators []
+    (vec (set
+          (apply concat
+                 (map (fn [key]
+                        (let [hsh (get prop-graph key)]
+                          (concat
+                           (map #(vec (list % (name key))) (get hsh :in-cells))
+                           (map #(vec (list (name key) %)) (get hsh :out-cells)))))
+                      (keys prop-graph))))))
+#+end_src
+
 * usage
 ** doubling a number -- simplest
 #+begin_src clojure
-  (cell in 0)
-  (cell out 0)
-  (propagator doubler [in] [out] (* 2 in))
+  (cell in-c 0)
+  (cell out-c 0)
+  (propagator doubler [in-c] [out-c] (* 2 in))
   ;; then any updates to in
-  (set-cell in 1)
+  (set-cell in-c 1)
   ;; will propagate to out
-  @out
+  @out-c
 #+end_src
 
 ** square roots -- heron
-results in errors...
-
 #+begin_src clojure
   (cell guess 1)
   (cell x 9)
@@ -95,8 +117,8 @@ results in errors...
   (propagator enough [x guess] [done]
     (if (< (abs (- (* guess guess) x)) @margin) true false))
   
-  (propagator heron [x guess] [guess]
-    (if (enough x guess)
+  (propagator heron [x done guess] [guess]
+    (if done
       guess
       (/ (+ guess (/ x guess)) 2.0)))
 #+end_src
-- 
2.11.4.GIT