diff --git a/dfs.scm b/dfs.scm
index 8f0d552..be06d96 100644
--- a/dfs.scm
+++ b/dfs.scm
@@ -70,9 +70,9 @@
 (define (dfs->list dfs-node)
   (list (dfs-name dfs-node) (dfs-adjacencies dfs-node) (dfs-ignored dfs-node)))
 
-(define (dfs-lookup-node node-name dag)
+(define (dfs-lookup-node pred node-name dag)
   (find (lambda (candidate) 
-	  (string=? (dfs-name candidate) node-name))
+	  (pred (dfs-name candidate) node-name))
 	dag))
 
 ;;; 
@@ -100,7 +100,8 @@
 ;;; unresolveable in the list of all node-names.
 ;;; 
 (define (dfs dag . maybe-arg)
-  (let-optionals maybe-arg ((auto-leafs? #t))
+  (let-optionals maybe-arg ((pred string=?)
+			    (auto-leafs? #t))
     (set! time 0)
     (let ((node-names (map dfs-name dag)))
       (if (not (null? node-names))
@@ -113,11 +114,11 @@
 		(let for-all-nodes ((node-name (car node-names))
 				    (nodes-to-do (cdr node-names))
 				    (current-dag dag))
-		  (let ((current-node (dfs-lookup-node node-name current-dag)))
+		  (let ((current-node (dfs-lookup-node pred node-name current-dag)))
 		    (cond 
 		     ((eq? (dfs-color current-node) (color white))
-		      (let ((new-dag (dfs-visit current-dag 
-						current-node auto-leafs?)))
+		      (let ((new-dag (dfs-visit current-dag current-node 
+						pred auto-leafs?)))
 			(if (not (null? nodes-to-do))
 			    (for-all-nodes (car nodes-to-do) 
 					   (cdr nodes-to-do) 
@@ -131,7 +132,7 @@
 		'())
 	  node-names))))
 
-(define (dfs-visit dag node auto-leafs?)
+(define (dfs-visit dag node pred auto-leafs?)
   ;;  (dfs-dag-show dag node)
   (let ((name (dfs-name node))
 	(adjs (dfs-adjacencies node))
@@ -142,12 +143,12 @@
       (if (not (null? adjs))
 	  (let for-all-adjs ((current-adj (car adjs))
 			     (todo-adjs (cdr adjs)))
-	    (let ((maybe-node (dfs-lookup-node current-adj current-dag)))
+	    (let ((maybe-node (dfs-lookup-node pred current-adj current-dag)))
 	      (if maybe-node
 		  (begin 
 		    (if (eq? (dfs-color maybe-node) (color white))
-			(let ((next-dag (dfs-visit current-dag 
-						   maybe-node auto-leafs?)))
+			(let ((next-dag (dfs-visit current-dag maybe-node 
+						   pred auto-leafs?)))
 			  (set! current-dag next-dag))
 			(if (eq? (dfs-color maybe-node) (color grey))
 			    (error "dfs-visit: cycle detected; node-name: "
@@ -155,8 +156,8 @@
 		  (if auto-leafs? 
 		      (let ((leaf (really-make-dfs current-adj '() 
 						   (color white) 0 #f)))
-			(set! current-dag (dfs-visit (cons leaf current-dag) 
-						     leaf auto-leafs?)))
+			(set! current-dag (dfs-visit (cons leaf current-dag) leaf 
+						     pred auto-leafs?)))
 		      (error "dfs-visit: unresolveable adjacency: "
 			     current-adj))))
 	    (if (not (null? todo-adjs))