Import Upstream version 3a5upstream/3a5

1 files changed, 17 insertions, 14 deletions

diff --git a/collect.scm b/collect.scm
index 05bc2cf..d4ccb6f 100644
--- a/collect.scm
+++ b/collect.scm
@@ -117,20 +117,23 @@
 )
 ;@
 (define (reduce <proc> <seed> . <collections>)
-   (let ( (max+1 (collect:size (car <collections>)))
-          (generators (map collect:gen-elts <collections>))
-        )
-     (let loop ( (count 0) )
-       (cond
-          ((< count max+1)
-           (set! <seed>
-                 (apply <proc> <seed> (map (lambda (g) (g)) generators)))
-           (loop (collect:add1 count))
-          )
-          (else <seed>)
-     ) )
-)  )
-
+  (define (reduce-init pred? init lst)
+    (if (null? lst)
+	init
+	(reduce-init pred? (pred? init (car lst)) (cdr lst))))
+  (if (null? <collections>)
+      (cond ((null? <seed>) <seed>)
+	    ((null? (cdr <seed>)) (car <seed>))
+	    (else (reduce-init <proc> (car <seed>) (cdr <seed>))))
+      (let ((max+1 (collect:size (car <collections>)))
+	    (generators (map collect:gen-elts <collections>)))
+	(let loop ((count 0))
+	  (cond
+	   ((< count max+1)
+	    (set! <seed>
+		  (apply <proc> <seed> (map (lambda (g) (g)) generators)))
+	    (loop (collect:add1 count)))
+	   (else <seed>))))))
 
 
 ;;@ pred true for every elt?