Fix how defaults are derived from history.

diff --git a/v7/src/edwin/prompt.scm b/v7/src/edwin/prompt.scm
index 894e42a09a3de43027f814fcc1ff7d8e4043c34a..5fd687046b4c00d341ea2808f5ec259e91af74fa 100644 (file)
--- a/v7/src/edwin/prompt.scm
+++ b/v7/src/edwin/prompt.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;; $Id: prompt.scm,v 1.176 1999/01/28 05:44:43 cph Exp $
+;;; $Id: prompt.scm,v 1.177 1999/01/28 05:59:00 cph Exp $
 ;;;
 ;;; Copyright (c) 1986, 1989-1999 Massachusetts Institute of Technology
 ;;;
@@ -211,12 +211,10 @@
                                             (write-to-string string)))
              #t
              (let ((thunk (typein-editor-thunk (options/mode *options*))))
-               (if (and (eq? type 'INSERTED-DEFAULT) string)
-                   (begin
-                     (set-options/default-string! options #f)
-                     (lambda ()
-                       (insert-string string)
-                       ((thunk))))
+               (if (and string (eq? type 'INSERTED-DEFAULT))
+                   (lambda ()
+                     (insert-string string)
+                     ((thunk)))
                    thunk)))))))
     (record-in-history! value (options/history options))
     value))
@@ -444,11 +442,11 @@
 (define (history->default-string options)
   (let ((history (options/history options))
        (index (options/history-index options)))
-    (if (let ((length (history-length history)))
-         (and (> length 0)
-              (not (< index length))))
-       (error "History index out of range:" index))
-    (if (not (memq 'DEFAULT-STRING (options/seen options)))
+    (if (and (not (options/default-string options))
+            (not (memq 'DEFAULT-STRING (options/seen options)))
+            (let ((length (history-length history)))
+              (and (> length 0)
+                   (< index length))))
        (set-options/default-string! options (history-item history index)))))
 \f
 ;;;; String Prompt Modes