289 lines
9.6 KiB
Plaintext
289 lines
9.6 KiB
Plaintext
Scsh 0.5.2 Release notes -*- outline -*-
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We are pleased to release scsh version 0.5.2. The new release has many bug
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fixes, improvements and new features.
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The text below gives a general description of scsh, instructions for obtaining
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it, pointers to discussion forums, and a description of the new features in
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release 0.5.2. (Emacs should display this document is in outline mode. Say
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c-h m for instructions on how to move through it by sections (e.g., c-c c-n,
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c-c c-p).)
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This release is the first new release of scsh in over a year. We've been
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using it, and have had no problems. However, we only recommend eager users
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download it. We'll upgrade it to a 0.5.3 release after a week or two, when
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this release has been shaken out.
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* Contents
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==========
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What is scsh
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Scsh as a scripting language
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Scsh as a systems-programming language
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Scsh is a portable programming environment
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Obtaining and installing scsh
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Getting in touch
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The World-Wide What?
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New in this release
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Scsh is now "open source."
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Scsh is now on Win32
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CVS repository will be public-readable
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New char-sets and char-set operations
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New regular expression system
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New libraries
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Renaming
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Bugfixes
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Thanks
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* What is scsh
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==============
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Scsh is a broad-spectrum systems-programming environment for Unix embedded
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in R4RS Scheme.
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** Scsh as a scripting language
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-------------------------------
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Scsh has a high-level process notation for doing shell-script like tasks:
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running programs, establishing pipelines and I/O redirection. For example, the
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shell pipeline
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gunzip < paper.tex.gz | detex | spell | lpr -Ppulp &
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would be written in scsh as
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(& (| (gunzip) (detex) (spell) (lpr -Ppulp)) ; Background a pipeline
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(< paper.tex.gz)) ; with this redirection
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Scsh embeds this process notation within a full Scheme implementation.
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The process notation is realized as a set of macro definitions, and is
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carefully designed to allow full integration with standard Scheme code.
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Scsh isn't Scheme-like; it is Scheme.
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At the scripting level, scsh also has an Awk design, also implemented
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as a macro that can be embedded inside general Scheme code.
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Scripts can be written as standalone Scheme source files, with a leading
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#!/usr/local/bin/scsh -s
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trigger line.
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** Scsh as a systems-programming language
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-----------------------------------------
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Scsh additionally provides the low-level access to the operating system
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normally associated with C. The current release provides full access to Posix,
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plus important non-Posix extensions, such as complete sockets support.
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"Complete Posix" means: fork, exec & wait, sockets, full read, write, open &
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close, seek & tell, complete file-system access, including stat,
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chmod/chgrp/chown, symlink, FIFO & directory access, tty & pty support, file
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locking, pipes, select, file-name pattern-matching, time & date, environment
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variables, signal handlers, and more.
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In brief, you can now write Unix systems programs in Scheme instead of C.
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For example, we have implemented an extensible HTTP server at MIT entirely
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in scsh.
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As important as full access to the OS is the manner in which it is provided.
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Scsh integrates the OS support into Scheme in a manner which respects the
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general structure of the language. The details of the design are discussed
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in a joint MIT Lab for Computer Science/University of Hong Kong technical
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report, "A Scheme Shell," also to appear in a revised format in the *Journal
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of Lisp and Symbolic Computation." This paper is also available by ftp:
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ftp://ftp-swiss.ai.mit.edu/pub/su/scsh/scsh-paper.ps
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** Scsh is a portable programming environment
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---------------------------------------------
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Scsh is designed for portability. It is implemented on top of Scheme 48,
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a byte-code-interpreter Scheme implementation. The Scheme 48 virtual machine
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can be compiled on any system with a C compiler; the rest of Scheme 48 is
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machine-independent across 32-bit processors. Scsh's OS interface is
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also quite portable, providing a consistent interface across different
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Unix platforms. We currently have scsh implementations for:
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AIX
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BSD/OS
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CXUX
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FreeBSD
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HP-UX
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IRIX
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Linux
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NetBSD
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NeXTStep
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Solaris
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SunOS
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Ultrix
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Win32
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Scsh code should run without change across these systems.
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Porting to new platforms is usually not difficult.
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* Obtaining and installing scsh
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===============================
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You can get a copy of scsh via anonymous ftp, from
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ftp://ftp-swiss.ai.mit.edu/pub/su/scsh/scsh.tar.gz
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The tar file includes a detailed manual and a paper describing
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the design of the system.
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For the lazily curious, we also have the manual separately available as
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ftp://ftp-swiss.ai.mit.edu/pub/su/scsh/scsh-manual.ps
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Just click 'n view.
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You *should* be able to build scsh on the standard platforms with exactly five
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commands: gunzip, tar, cd, ./configure, and make. The configure script figures
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out the special flags and switches needed to make the build work (thanks to
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the GNU project for the autoconfig tool that makes this possible).
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After doing the make, you can start up a Scheme shell and try it out
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by saying
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./scshvm -o ./scshvm -i ./scsh/scsh.image
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See the manual for full details on the command-line switches.
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If it's harder than this, and your system is standard, we'd like to know
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about it.
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* Getting in touch
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==================
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There are two main ways to join in scsh-related discussion: the mailing-list
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scsh@zurich.ai.mit.edu
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and the netnews group
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comp.lang.scheme.scsh
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These two forums are exactly equivalent, being bi-directionally gatewayed
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at MIT.
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Bugs can be reported to
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scsh-bugs@zurich.ai.mit.edu
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If you do not receive the alt netnews hierarchy, or wish to join the mailing
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list for other reasons, send mail to
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scsh-request@zurich.ai.mit.edu
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* The World-Wide What?
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======================
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We even have one of those URL things:
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http://www-swiss.ai.mit.edu/scsh/
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* New in this release
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=====================
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** Scsh is now "open source."
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We finally got around to tacking an ideologically hip copyright
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onto the source. (Not that we ever cared before what you did with
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the system...) The Scheme 48 authors have also graciously retrofitted
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a BSD-style open-source copyright onto the underlying Scheme 48 0.36
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platform for us. The whole system is now open source, top-to-bottom.
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Take all the code you like; we'll just write more.
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** Scsh is now on Win32
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Scsh will now build and run using Cygwin B20.1. This was only tested
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on Windows NT 4.0, but presumably things could work on other Cygwin
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platforms such as Win95 or Win98. Cygwin is available from:
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http://sourceware.cygnus.com/cygwin/
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** CVS repository will be public-readable
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We will add further information to the web-site as soon as possible.
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** New char-sets and char-set operations
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See the manual for more information on using character sets
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for text processing. Also, see the ccp package in scsh/scsh/lib
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for a new library providing character->character partial maps,
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which are also useful for general string processing.
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** New regular expression system
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There's a whole new regexp package in scsh. There's a new,
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s-expression-based notation for regexps, called SRE's. The new
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notation has been integrated into the AWK macro and field-parser functions.
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The older Posix notation is still supported for backwards compatibility.
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There's a whole chapter on regexps in the new manual; it has full details.
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The previous AWK and field-reader system is provided in a
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backwards-compatibility package. See package obsolete-awk-package
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in scsh-package.scm.
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** New libraries
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The SRFI-1 list library is available, in the list-lib package.
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There is a large, powerful string-processing library available
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in the string-lib package. See the directory scsh/scsh/lib/ for
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documentation and source.
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These libraries make basic list and string hacking very straightforward.
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** Renaming
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We are shifting from a reduce-foo convention to a more standard
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foo-fold convention. This has caused the following renamings:
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reduce-char-set => char-set-fold
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reduce-port => port-fold
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The older names are still bound, but are deprecated and will likely
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go away in a future release.
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String utilities INDEX and RINDEX are gone. Use the string-lib procedures
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instead.
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** Bugfixes
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Over a year's worth of bug fixes. In particular, the old problems with the
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signal system blowing up builds on some of the more obscure Unix systems
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have been fixed.
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* Thanks
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========
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We would like to thank the members of local-resistance cells for the
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Underground everywhere for bug reports, bug fixes, design review and comments
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that were incorporated into this release. We really appreciate their help,
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particularly in the task of porting scsh to new platforms.
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Alan Bawden
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Jim Blandy
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Per Bothner
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Tom Breton
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Christopher Browne
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Sean Doran
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Ray Dillinger
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Allyn Dimock
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Scott Draves
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Lutz Euler
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Kevin Esler
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Jeremy Fitzhardinge
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Noah Friedman
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Martin Gasbichler
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Andy Gaynor
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Ian Grant
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Eric Hanchrow
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Karl Hegbloom
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Johann Hibschman
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Ian Horswill & the Northwestern Scheme wizards
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Gary Houston
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Graham Hughes
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Jarmo Hurri
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Lars Kellogg-Stedman
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Andre Koehoerst
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Hannu Koivisto
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Shriram Krishnamurthi
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Jakob Lichtenberg
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Eric Marsden
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Peter C. Olsen
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Willliam Pippin
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David Rush
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Michael Schinz
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Manuel Serrano
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Mark Shirle
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Bill Sommerfeld
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Mike Sperber
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Harvey J. Stein
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Pawel Turnau
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Rob Warnock
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Kenneth R. Westerback
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We'd like to thank everyone else for their patience; this release seemed like
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a long time coming.
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Brought to you by the Scheme Underground. Go forth and write elegant systems
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programs.
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-Olin Shivers, Brian Carlstrom & Martin Gasbichler
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Cambridge
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29 September 1999
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