#| pwd-prompt.jl -- Prompt for a confidential answer (i.e. a password)

   $Id: pwd-prompt.jl,v 1.6 2000/09/26 23:11:53 john Exp $

   Copyright (C) 1998, 2000 John Harper <john@dcs.warwick.ac.uk>

   This file is part of librep.

   librep 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.

   librep 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 librep; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|#

(declare (in-module rep.system))

(open-structures '(rep.regexp rep.io.streams rep.lang.math))

;;;###autoload
(defun pwd-prompt (prompt)
  "Prompt for a confidential string, with PROMPT as the title string. The
contents of the prompt will be masked out whilst being entered."
  (when (zerop (system "stty -echo"))
    (unwind-protect
	(progn
	  (write standard-error prompt)
	  (unless (string-match "\s$" prompt)
	    (write standard-error #\space ))
	  (flush-file standard-error)
	  (let ((string (read-line standard-input)))
	    (when (string-match "\n$" string)
	      (setq string (substring string 0 (match-start))))
	    (write standard-error #\newline)
	    string))
      (system "stty echo"))))