Add support for readline function.

* readline.scm: New module.
* boot-9.scm (repl-reader): New function.
(scm-style-repl): Call repl-reader, instead of doing the reading
ourselves.  Remove repl-report-reset; it was never used for
anything.
(top-repl): If we've got the readline primitives, then redefine
repl-reader to use them.
If we've got the readline primitives, import the readline module.

2 files changed, 112 insertions, 11 deletions

diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
index c1e27ab0d..34f603251 100644
--- a/ice-9/boot-9.scm
+++ b/ice-9/boot-9.scm
@@ -2424,11 +2424,18 @@
 (define before-read-hook '())
 (define after-read-hook '())
 
+;;; The default repl-reader function.  We may override this if we've
+;;; the readline library.
+(define repl-reader
+  (lambda (prompt)
+    (display prompt)
+    (force-output)
+    (read (current-input-port))))
+
 (define (scm-style-repl)
   (letrec (
 	   (start-gc-rt #f)
 	   (start-rt #f)
-	   (repl-report-reset (lambda () #f))
 	   (repl-report-start-timing (lambda ()
 				       (set! start-gc-rt (gc-run-time))
 				       (set! start-rt (get-internal-run-time))))
@@ -2454,17 +2461,19 @@
 		 ((char=? ch #\newline)
 		  (read-char))))))
 	   (-read (lambda ()
-		    (if scm-repl-prompt
-			(begin
-			  (display (cond ((string? scm-repl-prompt)
-					  scm-repl-prompt)
-					 ((thunk? scm-repl-prompt)
-					  (scm-repl-prompt))
-					 (else "> ")))
-			  (force-output)
-			  (repl-report-reset)))
+		    ;; It would be nice if we could run this after the
+		    ;; first prompt was printed, but with readline
+		    ;; that's not possible, so we punt.
 		    (run-hooks before-read-hook)
-		    (let ((val (read (current-input-port))))
+		    (let ((val
+			   (let ((prompt (cond ((string? scm-repl-prompt)
+						scm-repl-prompt)
+					       ((thunk? scm-repl-prompt)
+						(scm-repl-prompt))
+					       (scm-repl-prompt "> ")
+					       (else ""))))
+			     (repl-reader prompt))))
+
 		      ;; As described in R4RS, the READ procedure updates the
 		      ;; port to point to the first characetr past the end of
 		      ;; the external representation of the object.  This
@@ -2747,6 +2756,17 @@
 
      ;; the protected thunk.
      (lambda ()
+
+       ;; If we've got readline, use it to prompt the user.  This is a
+       ;; kludge, but we'll fix it soon.  At least we only get
+       ;; readline involved when we're actually running the repl.
+       (if (memq 'readline *features*)
+	   (begin
+	     (set-current-input-port (readline-port))
+	     (set! repl-reader
+		   (lambda (prompt)
+		     (set-readline-prompt! prompt)
+		     (read)))))
        (scm-style-repl))
 
      ;; call at exit.
@@ -2811,6 +2831,15 @@
     (define-module (guile) :use-module (ice-9 regex)))
 
 
+;;; Load readline code if rreadline primitives are available.
+;;;
+;;; Ideally, we wouldn't do this until we were sure we were actually
+;;; going to enter the repl, but autoloading individual functions is
+;;; clumsy at the moment.
+(if (memq 'readline *features*)
+    (define-module (guile) :use-module (ice-9 readline)))
+
+
 ;;; {Check that the interpreter and scheme code match up.}
 
 (let ((show-line
diff --git a/ice-9/readline.scm b/ice-9/readline.scm
new file mode 100644
index 000000000..cb47d6522
--- /dev/null
+++ b/ice-9/readline.scm
@@ -0,0 +1,72 @@
+;;;; readline.scm --- support functions for command-line editing
+;;;;
+;;;; 	Copyright (C) 1997 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.
+;;;; 
+;;;; Contributed by Daniel Risacher <risacher@worldnet.att.net>.
+
+(define-module (ice-9 readline))
+
+(define prompt "")
+
+(define (make-readline-port)
+  (let ((read-string "")
+	(string-index -1))
+    (letrec ((get-character
+	      (lambda ()
+		(cond 
+		 ((eof-object? read-string)
+		  read-string)
+		 ((>= string-index (string-length read-string))
+		  (begin
+		    (set! string-index -1)
+		    #\nl))
+		 ((= string-index -1)
+		  (begin
+		    (set! read-string (readline prompt))
+		    (set! string-index 0)
+		    (if (not (eof-object? read-string))
+			(begin
+			  (or (string=? read-string "")
+			      (add-history read-string))
+			  (get-character))
+			read-string)))
+		 (else 
+		  (let ((res (string-ref read-string string-index)))
+		    (set! string-index (+ 1 string-index))
+		    res))))))	      
+      (make-soft-port
+       (vector write-char display #f get-character #f)
+       "rw"))))
+
+;;; We only create one readline port.  There's no point in having
+;;; more, since they would all share the tty and history ---
+;;; everything except the prompt.  And don't forget the
+;;; compile/load/run phase distinctions.
+(define the-readline-port #f)
+
+(define-public (readline-port)
+  (if (not the-readline-port)
+      (set! the-readline-port (make-readline-port)))
+  the-readline-port)
+
+(define-public (set-readline-prompt! p)
+  (set! prompt p))
+
+   
+;(define myport (make-readline-port))
+;(define (doit)
+;  (set-current-input-port myport))