diff --git a/collects/mred/mred.ss b/collects/mred/mred.ss
index 52c79a58..620c5654 100644
--- a/collects/mred/mred.ss
+++ b/collects/mred/mred.ss
@@ -7402,72 +7402,82 @@
 				(format "end index outside the range [~a,~a]: " start last)
 				end))))
     ;; Create the port:
-    (let-values ([(pipe-r pipe-w) (make-pipe)])
-      (let* ([end (if (eq? end 'end) (send text last-position) end)]
-	     [snip (send text find-snip start 'after-or-none)]
-	     [next? #f]
-	     [pos 0]
-	     [lock-semaphore (make-semaphore 1)]
-	     [update-str-to-snip
-	      (lambda ()
-		(if snip
-		    (let ([snip-start (send text get-snip-position snip)])
-		      (cond
-		       [(snip-start . >= . end)
-			(set! snip #f)
-			(set! next? #f)]
-		       [(is-a? snip wx:string-snip%)
-			(display (send snip get-text 0 (send snip get-count)) pipe-w)
-			(set! next? #t)]
-		       [else
-			(set! next? #f)]))
-		    (set! next? #f)))]
-	     [next-snip
-	      (lambda ()
-		(set! snip (send snip next))
-		(set! pos 0)
-		(update-str-to-snip))]
-	     [read-chars (lambda (to-str)
-			   (cond
-			    [next?
-			     (next-snip)
-			     0]
-			    [snip
-			     (let ([the-snip snip])
-			       (lambda (file line col ppos)
-				 (if (is-a? the-snip readable-snip<%>)
-				     (with-handlers ([exn:special-comment?
-						      (lambda (exn)
-							;; implies "done"
-							(next-snip)
-							(raise exn))])
-				       (let-values ([(val size done?)
-						     (send the-snip read-one-special pos file line col ppos)])
-					 (if done?
-					     (next-snip)
-					     (set! pos (add1 pos)))
-					 (values val size)))
-				     (begin
-				       (next-snip)
-				       (values (send the-snip copy) 1)))))]
-			    [else eof]))]
-	     [close (lambda () (void))]
-	     [port (make-custom-input-port 
-		    (lambda (s)
-		      (if (char-ready? pipe-r)
-			  (read-string-avail!* s pipe-r)
-			  (parameterize ([break-enabled #f])
-			    (if (semaphore-try-wait? lock-semaphore)
-				(dynamic-wind
-				    void
-				    (lambda () (read-chars s))
-				    (lambda () (semaphore-post lock-semaphore)))
-				(make-semaphore-peek lock-semaphore)))))
-		    #f ; no peek
-		    close)])
-	(update-str-to-snip)
-	(port-count-lines! port)
-	port))]
+    (with-method ([gsp (text get-snip-position)])
+      (let-values ([(pipe-r pipe-w) (make-pipe)])
+	(let* ([get-text-generic (generic wx:snip% get-text)]
+	       [get-count-generic (generic wx:snip% get-count)]
+	       [next-generic (generic wx:snip% next)]
+	       [end (if (eq? end 'end) (send text last-position) end)]
+	       [snip (send text find-snip start 'after-or-none)]
+	       [next? #f]
+	       [pos 0]
+	       [lock-semaphore (make-semaphore 1)]
+	       [update-str-to-snip
+		(lambda (to-str)
+		  (if snip
+		      (let ([snip-start (gsp snip)])
+			(cond
+			 [(snip-start . >= . end)
+			  (set! snip #f)
+			  (set! next? #f)
+			  0]
+			 [(is-a? snip wx:string-snip%)
+			  (set! next? #t)
+			  (let ([c (min (send-generic snip get-count-generic) (- end snip-start))])
+			    (display (send-generic snip get-text-generic 0 c) pipe-w)
+			    0)]
+			 [else
+			  (set! next? #f)
+			  0]))
+		      (begin
+			(set! next? #f)
+			0)))]
+	       [next-snip
+		(lambda (to-str)
+		  (set! snip (send-generic snip next-generic))
+		  (set! pos 0)
+		  (update-str-to-snip to-str))]
+	       [read-chars (lambda (to-str)
+			     (cond
+			      [next?
+			       (next-snip to-str)]
+			      [snip
+			       (let ([the-snip snip])
+				 (lambda (file line col ppos)
+				   (if (is-a? the-snip readable-snip<%>)
+				       (with-handlers ([exn:special-comment?
+							(lambda (exn)
+							  ;; implies "done"
+							  (next-snip "")
+							  (raise exn))])
+					 (let-values ([(val size done?)
+						       (send the-snip read-one-special pos file line col ppos)])
+					   (if done?
+					       (next-snip "")
+					       (set! pos (add1 pos)))
+					   (values val size)))
+				       (begin
+					 (next-snip "")
+					 (values (send the-snip copy) 1)))))]
+			      [else eof]))]
+	       [close (lambda () (void))]
+	       [port (make-custom-input-port 
+		      (lambda (s)
+			(if (char-ready? pipe-r)
+			    (read-string-avail!* s pipe-r)
+			    (parameterize ([break-enabled #f])
+			      (if (semaphore-try-wait? lock-semaphore)
+				  ;; If there's an error here, the
+				  ;; port will remain locked.
+				  (let ([v (read-chars s)])
+				    (semaphore-post lock-semaphore)
+				    v)
+				  (make-semaphore-peek lock-semaphore)))))
+		      #f ; no peek
+		      close)])
+	  (update-str-to-snip "")
+	  (port-count-lines! port)
+	  port)))]
    [(text start) (open-input-text-editor text start 'end)]
    [(text) (open-input-text-editor text 0 'end)]))