#| -*-Scheme-*-

$Id: comhst.scm,v 1.11 2007/01/05 21:19:23 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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 of the License, or (at
your option) any later version.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

|#

;;;; Command interpreter history
;;; Translated from "comint.el", by Olin Shivers.

(declare (usual-integrations))

(define-variable-per-buffer comint-input-ring-size
  "Size of input history ring."
  30)

(define-variable comint-input-ring "" #f)
(variable-permanent-local! (ref-variable-object comint-input-ring))

(define-variable comint-last-input-match "" #f)
(variable-permanent-local! (ref-variable-object comint-last-input-match))

(define comint-input-ring-tag '(COMINT-INPUT-RING))

(define (comint-record-input ring string)
  (if (or (ring-empty? ring)
	  (not (string=? string (ring-ref ring 0))))
      (ring-push! ring string)))

(define-command comint-previous-input
  "Cycle backwards through input history."
  "*p"
  (lambda (argument)
    (let ((point (current-point))
	  (ring (ref-variable comint-input-ring)))
      (let ((size (+ (ring-size ring) 1)))
	(let ((index
	       (modulo (+ argument
			  (command-message-receive comint-input-ring-tag
			    (lambda (index left right)
			      (delete-string left right)
			      (set-current-mark! left)
			      index)
			    (lambda ()
			      (push-current-mark! point)
			      (cond ((positive? argument) 0)
				    ((negative? argument) 2)
				    (else 1)))))
		       size)))
	  (message (number->string index))
	  (if (positive? index)
	      (without-interrupts
	       (lambda ()
		 (let ((start (mark-temporary-copy point)))
		   (insert-string (ring-ref ring (- index 1)) point)
		   (set-command-message! comint-input-ring-tag
					 index
					 (mark-left-inserting-copy start)
					 (mark-right-inserting-copy point)))))
	      (set-command-message! comint-input-ring-tag
				    index point point)))))))
	 
(define-command comint-next-input
  "Cycle forwards through input history."
  "*p"
  (lambda (argument)
    ((ref-command comint-previous-input) (- argument))))

(define-command comint-history-search-backward
  "Search backwards through the input history for a matching substring."
  (lambda ()
    (list (prompt-for-string "History search backward"
			     (ref-variable comint-last-input-match))))
  (lambda (string)
    (comint-history-search string true)))

(define-command comint-history-search-forward
  "Search forwards through the input history for a matching substring."
  (lambda ()
    (list (prompt-for-string "History search forward"
			     (ref-variable comint-last-input-match))))
  (lambda (string)
    (comint-history-search string false)))

(define (comint-history-search string backward?)
  (let ((ring (ref-variable comint-input-ring))
	(syntax-table (ref-variable syntax-table))
	(pattern (re-compile-pattern (re-quote-string string) false)))
    (let ((size (+ (ring-size ring) 1)))
      (call-with-values
	  (lambda ()
	    (command-message-receive comint-input-ring-tag
	      values
	      (lambda ()
		(let ((point (current-point)))
		  (values (if backward? 0 size) point point)))))
	(lambda (start left right)
	  (let loop ((index start))
	    (let ((index (+ index (if backward? 1 -1))))
	      (cond ((if backward? (>= index size) (< index 0))
		     (set-command-message! comint-input-ring-tag
					   start left right)
		     (editor-failure "Not found"))
		    ((re-string-search-forward pattern
					       (ring-ref ring (- index 1))
					       #f
					       syntax-table)
		     (set-variable! comint-last-input-match string)
		     ((ref-command comint-previous-input) (- index start)))
		    (else
		     (loop index))))))))))