Implement PROMPT-OPTIONS-DEFAULT-STRING to determine whether a set of

options specifies a default prompt string.

diff --git a/v7/src/edwin/edwin.pkg b/v7/src/edwin/edwin.pkg
index 15c27b17db5278d8066892cb84e129e90b814093..d81e3a8890ba0fda0143c3abf98847b07c0f3d99 100644 (file)
--- a/v7/src/edwin/edwin.pkg
+++ b/v7/src/edwin/edwin.pkg
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: edwin.pkg,v 1.274 2001/09/21 02:56:15 cph Exp $
+$Id: edwin.pkg,v 1.275 2001/10/30 19:25:15 cph Exp $
 
 Copyright (c) 1989-2001 Massachusetts Institute of Technology
 
@@ -469,6 +469,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
          edwin-mode$minibuffer-local-yes-or-no
          edwin-variable$enable-recursive-minibuffers
          edwin-variable$completion-auto-help
+         lookup-prompt-option
          pop-up-completions-list
          pop-up-generated-completions
          prompt-for-alist-value
@@ -486,6 +487,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
          prompt-for-variable
          prompt-for-yes-or-no?
          prompt-history-strings
+         prompt-options-default-string
          set-prompt-history-strings!
          standard-completion
          temporary-typein-message

diff --git a/v7/src/edwin/prompt.scm b/v7/src/edwin/prompt.scm
index 2f75517c7b84351267c227e2c67d286bd4f52e26..1e92ffec5037b788710c459dec421a74b99cf9ee 100644 (file)
--- a/v7/src/edwin/prompt.scm
+++ b/v7/src/edwin/prompt.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;; $Id: prompt.scm,v 1.197 2001/09/25 12:57:26 cph Exp $
+;;; $Id: prompt.scm,v 1.198 2001/10/30 19:25:08 cph Exp $
 ;;;
 ;;; Copyright (c) 1986, 1989-2001 Massachusetts Institute of Technology
 ;;;
@@ -359,6 +359,22 @@
          (else
           (error "Illegal options tail:" options)))))
 
+(define (lookup-prompt-option options keyword default)
+  ;; If there are multiple instances of KEYWORD, return the last.
+  (let loop ((options options) (winner #f))
+    (if (pair? options)
+       (begin
+         (if (not (pair? (cdr options)))
+             (error "Options list has odd length:" options))
+         (loop (cddr options)
+               (if (eq? keyword (car options)) options winner)))
+       (begin
+         (if (not (null? options))
+             (error "Illegal options tail:" options))
+         (if winner
+             (cadr winner)
+             default)))))
+
 (define prompt-options-table
   '())
 \f
@@ -463,6 +479,18 @@
               (and (> length 0)
                    (< index length))))
        (set-options/default-string! options (list-ref (cdr history) index)))))
+
+(define (prompt-options-default-string options)
+  (or (lookup-prompt-option options 'DEFAULT-STRING #f)
+      (let ((index (lookup-prompt-option options 'HISTORY-INDEX #f)))
+       (and index
+            (<= 0 index)
+            (let ((strings
+                   (cdr
+                    (name->history
+                     (lookup-prompt-option options 'HISTORY #f)))))
+              (and (< index (length strings))
+                   (list-ref strings index)))))))
 \f
 ;;;; String Prompt Modes