diff --git a/scsh/procobj.scm b/scsh/procobj.scm
index 5849ab1..64008c1 100644
--- a/scsh/procobj.scm
+++ b/scsh/procobj.scm
@@ -55,7 +55,7 @@
 
 ;;; Is X a pid or a proc?
 
-(define (pid/proc? x) (or (proc? x) (and (integer? x) (>= pid 0))))
+(define (pid/proc? x) (or (proc? x) (and (integer? x) (>= x 0))))
 
 
 ;;; Process reaping
@@ -296,13 +296,12 @@
 (define reaped-procs '())	; Reaped, but not yet waited. 
 
 (define (filter-weak-ptr-list pred lis)
-  (reverse (reduce (lambda (result wptr)
-		     (let ((val (weak-pointer-ref wptr)))
-		       (if (and val (pred val))
-			   (cons wptr result)
-			   result)))
-		   '()
-		   lis)))
+  (foldr (lambda (wptr result) (let ((val (weak-pointer-ref wptr)))
+				 (if (and val (pred val))
+				     (cons wptr result)
+				     result)))
+	 '()
+	 list))
 
 ;;; Add a newly-reaped proc to the list.
 (define (add-reaped-proc! pid status)