Import Upstream version 4e6upstream/4e6

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+;; Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+;; 
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+;; 
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;; 
+;; You should have received a copy of the GNU General Public License
+;; along with this software; see the file COPYING.  If not, write to
+;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;;
+;; As a special exception, the Free Software Foundation gives permission
+;; for additional uses of the text contained in its release of GUILE.
+;;
+;; The exception is that, if you link the GUILE library with other files
+;; to produce an executable, this does not by itself cause the
+;; resulting executable to be covered by the GNU General Public License.
+;; Your use of that executable is in no way restricted on account of
+;; linking the GUILE library code into it.
+;;
+;; This exception does not however invalidate any other reasons why
+;; the executable file might be covered by the GNU General Public License.
+;;
+;; This exception applies only to the code released by the
+;; Free Software Foundation under the name GUILE.  If you copy
+;; code from other Free Software Foundation releases into a copy of
+;; GUILE, as the General Public License permits, the exception does
+;; not apply to the code that you add in this way.  To avoid misleading
+;; anyone as to the status of such modified files, you must delete
+;; this exception notice from them.
+;;
+;; If you write modifications of your own for GUILE, it is your choice
+;; whether to permit this exception to apply to your modifications.
+;; If you do not wish that, delete this exception notice.  
+
+;;  "Iedline.scm" Scheme interface to readline library
+;; Author: Radey Shouman
+
+;; Change both current-input-port and current-output-port to
+;; allow line editing of input.
+;; All output goes through a soft port in order to detect prompt 
+;; lines, i.e. lines unterminated by a newline.
+
+(define (make-edited-line-port)
+  (let ((prompt "")
+	(outp (default-output-port))
+	(inp (default-input-port))
+	(strp (call-with-input-string "" identity)))
+    (make-soft-port
+     (vector (lambda (c)
+	       (write-char c outp))
+	     (lambda (s)
+	       (display s outp)
+	       (or (zero? (string-length s))
+		   (eq? #\newline (string-ref s (- (string-length s) 1)))
+		   (begin
+		     (set! prompt (string-append "\r" s))
+		     (force-output outp))))
+	     (lambda ()
+	       (force-output outp))
+	     (lambda ()
+	       (let tail ((c (read-char strp)))
+		 (if (char? c) c
+		     (let ((str (read-edited-line prompt)))
+		       (if (string? str)
+			   (let ((n (string-length str)))
+			     (add-history str)
+			     (vector-set-length! str (+ 1 n))
+			     (string-set! str n #\newline)
+			     (set! strp (call-with-input-string
+					 str identity))
+			     (tail (read-char strp)))
+			   str)))))
+	     #f)
+     OPEN_BOTH)))
+
+(define line-editing
+  (let ((edit-port #f)
+	(oiport #f)
+	(ooport #f))
+    (lambda arg
+      (define past edit-port)
+      (cond ((null? arg))
+	    ((and (car arg) (not edit-port))
+	     (set! edit-port (make-edited-line-port))
+	     (set! oiport (set-current-input-port edit-port))
+	     (set! ooport (set-current-output-port edit-port)))
+	    (edit-port
+	     (set-current-input-port oiport)
+	     (set-current-output-port ooport)
+	     (set! edit-port #f)))
+      past)))
+
+(and 
+ (if (provided? 'unix) (isatty? (current-input-port)) #t)
+ (eq? (current-input-port) (default-input-port))
+ (not (getenv "EMACS"))
+ (line-editing #t))