From 8e983a9bfaed2d1ee56ac2a4f3330582d22c1246 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 12 Jul 2016 03:28:38 -0400
Subject: [PATCH] WIP

---
 deps.scm | 83 ++++++++++++++++++++++++++++++--------------------------
 1 file changed, 45 insertions(+), 38 deletions(-)

diff --git a/deps.scm b/deps.scm
index 4644ab60..d91fef71 100644
--- a/deps.scm
+++ b/deps.scm
@@ -13,49 +13,56 @@
     ;((d) (b)) ; circular dep!
     ((e))
    ))
-;; TODO: see http://www.electricmonk.nl/log/2008/08/07/dependency-resolving-algorithm/
 
-;; A dependency is a list (lib . deps)
-;; lib is the name, and deps are the edges.
-;; Goal is to resolve a list of dependencies into the appropriate order
+;; Goal is to resolve a list of dependencies into the appropriate order such 
+;; that no node is encountered before its dependencies.
 ;; We also need to raise an error if a circular dependency is found
+;; 
+;; A dependency list consists of: (name . edges)
+;; Where edges are all of the dependencies of name.
+;; 
+;; nodes is a list of many dependency lists.
+;;
+;; Based on code from:
+;; http://www.electricmonk.nl/log/2008/08/07/dependency-resolving-algorithm/
+(define (resolve-dependencies nodes)
+  (define (append-cell! cell value) (set-cdr! cell (cons value (cdr cell))))
+  (define (make-cell) (cons #f '()))
+  (define get-cell cdr)
+  (define (node->edges name) (assoc name nodes))
 
-;; TODO: consider loading all (lib . deps) into a table so we can easily get edges for a lib
+  ;; Create a new node that depends on all the others
+  (define (master-dependency)
+    (cons '(#f) (map car nodes)))
 
-(define (node->edges name)
-  (assoc name test2))
+  (define (dep-resolve node resolved seen)
+    ; DEBUG: (write node) (newline)
+    (append-cell! seen node)
+    (for-each
+      (lambda (edge)
+        (cond
+          ((not (assoc edge (get-cell resolved)))
+           (if (assoc edge (get-cell seen))
+               (error "Circular dependency detected" node edge))
+           (dep-resolve (node->edges edge) resolved seen))))
+      (cdr (node->edges (car node))))
+    (append-cell! resolved node)
+    resolved)
 
-(define result (cons #f '()))
-(define seen (cons #f '()))
+  (set! nodes (cons (master-dependency) nodes))
+  (let* ((resolved (dep-resolve (node->edges '(#f)) (make-cell) (make-cell)))
+         (deps (reverse (cdr (get-cell resolved))))) ;; cdr to get rid of master list
+    (map car deps)))
 
-(define (append-cell! cell value)
-  (set-cdr! cell (cons value (cdr cell))))
-(define get-cell cdr)
-
-(define (get-all-names)
-  (cons '(all) (map car test2)))
-
-(define (dep-resolve node resolved seen)
-  ;(write (car node))
-  (write node)
-  (newline)
-  (append-cell! seen node)
-  (for-each
-    (lambda (edge)
-      (cond
-        ((not (assoc edge (get-cell resolved)))
-         (if (assoc edge (get-cell seen))
-             (error "Circular dependency detected" node edge))
-         (dep-resolve (node->edges edge) resolved seen))))
-    (cdr (node->edges (car node))))
-  (append-cell! resolved node)
-)
-
-(set! test2 (cons (get-all-names) test2))
-;(write (get-all-names))
-;(newline)
-(dep-resolve (node->edges '(all)) result seen)
-;(dep-resolve (node->edges '(a)) result seen)
+(write (resolve-dependencies test2))
 (newline)
-(write (reverse (get-cell result)))
+(write (resolve-dependencies *test*))
+
+;  (set! test2 (cons (get-all-names) test2))
+;;(write (get-all-names))
+;;(newline)
+;(dep-resolve (node->edges '(all)) result seen)
+;;(dep-resolve (node->edges '(a)) result seen)
+;(newline)
+;(write (reverse (get-cell result)))