in PROVIDE-INPUT-FEATURES, don't advertise operations that aren't

supported.

diff --git a/v7/src/runtime/port.scm b/v7/src/runtime/port.scm
index d6ed67c12f10df08883db433178bf38b4ce72fad..168d64654c1c3e4e1ce56a33ef760695e0bb9f19 100644 (file)
--- a/v7/src/runtime/port.scm
+++ b/v7/src/runtime/port.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: port.scm,v 1.58 2008/07/26 05:12:20 cph Exp $
+$Id: port.scm,v 1.59 2008/08/18 06:40:18 cph Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -290,16 +290,18 @@ USA.
               char))))
        (unread-char
         (let ((defer (op 'UNREAD-CHAR)))
-          (lambda (port char)
-            (defer port char)
-            (set-port/unread?! port #t))))
+          (and defer
+               (lambda (port char)
+                 (defer port char)
+                 (set-port/unread?! port #t)))))
        (peek-char
         (let ((defer (op 'PEEK-CHAR)))
-          (lambda (port)
-            (let ((char (defer port)))
-              (transcribe-input-char char port)
-              (set-port/unread?! port #t)
-              char))))
+          (and defer
+               (lambda (port)
+                 (let ((char (defer port)))
+                   (transcribe-input-char char port)
+                   (set-port/unread?! port #t)
+                   char)))))
        (read-substring
         (let ((defer (op 'READ-SUBSTRING)))
           (lambda (port string start end)