diff --git a/core/io/streams/duplex/duplex.factor b/core/io/streams/duplex/duplex.factor
index 83e991b713..574735a9c5 100755
--- a/core/io/streams/duplex/duplex.factor
+++ b/core/io/streams/duplex/duplex.factor
@@ -1,75 +1,77 @@
-! Copyright (C) 2005 Slava Pestov.
+! Copyright (C) 2005, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
+USING: kernel continuations io accessors ;
 IN: io.streams.duplex
-USING: kernel continuations io ;
 
 ! We ensure that the stream can only be closed once, to preserve
 ! integrity of duplex I/O ports.
 
-TUPLE: duplex-stream in out closed? ;
+TUPLE: duplex-stream in out closed ;
 
 : <duplex-stream> ( in out -- stream )
     f duplex-stream construct-boa ;
 
+<PRIVATE
+
 ERROR: stream-closed-twice ;
 
-: check-closed ( stream -- )
-    duplex-stream-closed? [ stream-closed-twice ] when ;
+: check-closed ( stream -- stream )
+    dup closed>> [ stream-closed-twice ] when ; inline
 
-: duplex-stream-in+ ( duplex -- stream )
-    dup check-closed duplex-stream-in ;
+: in ( duplex -- stream ) check-closed in>> ;
 
-: duplex-stream-out+ ( duplex -- stream )
-    dup check-closed duplex-stream-out ;
+: out ( duplex -- stream ) check-closed out>> ;
+
+PRIVATE>
 
 M: duplex-stream stream-flush
-    duplex-stream-out+ stream-flush ;
+    out stream-flush ;
 
 M: duplex-stream stream-readln
-    duplex-stream-in+ stream-readln ;
+    in stream-readln ;
 
 M: duplex-stream stream-read1
-    duplex-stream-in+ stream-read1 ;
+    in stream-read1 ;
 
 M: duplex-stream stream-read-until
-    duplex-stream-in+ stream-read-until ;
+    in stream-read-until ;
 
 M: duplex-stream stream-read-partial
-    duplex-stream-in+ stream-read-partial ;
+    in stream-read-partial ;
 
 M: duplex-stream stream-read
-    duplex-stream-in+ stream-read ;
+    in stream-read ;
 
 M: duplex-stream stream-write1
-    duplex-stream-out+ stream-write1 ;
+    out stream-write1 ;
 
 M: duplex-stream stream-write
-    duplex-stream-out+ stream-write ;
+    out stream-write ;
 
 M: duplex-stream stream-nl
-    duplex-stream-out+ stream-nl ;
+    out stream-nl ;
 
 M: duplex-stream stream-format
-    duplex-stream-out+ stream-format ;
+    out stream-format ;
 
 M: duplex-stream make-span-stream
-    duplex-stream-out+ make-span-stream ;
+    out make-span-stream ;
 
 M: duplex-stream make-block-stream
-    duplex-stream-out+ make-block-stream ;
+    out make-block-stream ;
 
 M: duplex-stream make-cell-stream
-    duplex-stream-out+ make-cell-stream ;
+    out make-cell-stream ;
 
 M: duplex-stream stream-write-table
-    duplex-stream-out+ stream-write-table ;
+    out stream-write-table ;
 
 M: duplex-stream dispose
     #! The output stream is closed first, in case both streams
     #! are attached to the same file descriptor, the output
     #! buffer needs to be flushed before we close the fd.
-    dup duplex-stream-closed? [
-        t over set-duplex-stream-closed?
-        [ dup duplex-stream-out dispose ]
-        [ dup duplex-stream-in dispose ] [ ] cleanup
+    dup closed>> [
+        t >>closed
+        [ dup out>> dispose ]
+        [ dup in>> dispose ] [ ] cleanup
     ] unless drop ;