About SWL

Written by (in alphabetical order): Carl Bruggeman, Robert G. Burger, R. Kent Dybvig, Erik Hilsdale, Oscar Waddell, John Zuckerman, with contributions from Walter Kovaleski of Abstrax, Inc.

SWL development has been supported by the National Science Foundation (under grant number CDA-9312614), Indiana University, and Cadence Research Systems.

SWL is based on Scriptics' Tcl/Tk system and runs in Chez Scheme and/or Petite Chez Scheme.

SWL is distributed under the same terms as the Tcl/Tk system upon which it is based, as described under license below.

SWL is very much a work in progress, and is still in prerelease form. A few of its major deficiencies are listed below:

• The current thread schedular levies a large penalty on run-time performance (often in excess of 10%). This affects timings as well as performance.
• The global namespace is poluted by many hundreds of names that don't belong there, and redefining or assigning these names can cause SWL to malfunction.
• The HTML viewer is very incomplete and cannot even handle our own documentation properly. You're better off using Netscape to view the documentation.
• Many more aspects of SWL's appearance and behavior should be controlled by preferences, and it should be possible to save preferences from one use of SWL to the next.
• Many of the tools, including the stepper, graphical inspector, and profile viewer are out of date and are not included in the binary distribution.

SWL Source is available from http://www.cs.indiana.edu/proglang/swl. Feel free to grab it and (a) fix any bugs you find, (b) add any new features you like, (c) port it to the most recent version of Tcl/Tk if not already done, (d) port it to new the most recent version of Chez Scheme if not already done, or (e) port it to another Scheme system. Please let us know about any such changes at swl@cs.indiana.edu.

If you find a bug, please take a few minutes to isolate it and create a short file or sequence of expressions that exposes the bug. If you feel like fixing it yourself, please do! Send us the code that exposes the bug along with the required fix, and we'll put it into the next release. If you don't feel like fixing it yourself, send us the (short) code that exposes the bug and we'll try to track it down. In either case, please send us a transcript and/or complete description of the errant behavior. If we can't reproduce a problem, we can't fix it. Send all information about SWL bugs to swl@cs.indiana.edu.

SWL License

The authors hereby grant permission to use, copy, modify, distribute, and license this software and its documentation for any purpose, provided that existing copyright notices are retained in all copies and that this notice is included verbatim in any distributions. No written agreement, license, or royalty fee is required for any of the authorized uses. Modifications to this software may be copyrighted by their authors and need not follow the licensing terms described here, provided that the new terms are clearly indicated on the first page of each file where they apply.

IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

GOVERNMENT USE: If you are acquiring this software on behalf of the U.S. government, the Government shall have only "Restricted Rights" in the software and related documentation as defined in the Federal Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are acquiring the software on behalf of the Department of Defense, the software shall be classified as "Commercial Computer Software" and the Government shall have only "Restricted Rights" as defined in Clause 252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the authors grant the U.S. Government and others acting in its behalf permission to use and distribute the software in accordance with the terms specified in this license.

Chez Scheme and Petite Chez Scheme, within which SWL runs, are covered by separate agreements that you should have received when Chez Scheme or Petite Chez Scheme was installed.