110 lines
3.7 KiB
Groff
110 lines
3.7 KiB
Groff
We are pleased to release version 0.5 of scsh, the Scheme shell.
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* Scsh
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------
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Scsh is a Scheme system designed for systems programming and high-level
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scripting of Unix applications. It includes
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- a complete Posix interface from Scheme, including complete
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sockets support, signal handlers, and tty control;
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- a uniform interface to other generally-universal Unix features,
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such as symlinks and pseudo-terminals;
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- a library of generally useful tools for scripting applications,
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such as regular expressions;
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- macro support for a high-level process notation, allowing one to
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build pipelines of programs and redirect I/O, similar to Unix shells
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such as sh and csh;
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- a full R5RS-compliant Scheme, with important extensions: record types,
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exceptions, and modules;
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- command-line interface designed for writing scripts that are invoked
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with #! triggers on their first line.
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Scsh runs on most Unix platforms, including Linux, various BSD systems,
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Solaris, AIX, and Irix. It is implemented as an extension of Scheme 48,
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a portable, byte-code interpreter Scheme implementation.
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* Obtaining scsh
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----------------
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You may obtain the new release at the scsh web page
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http://www-swiss.ai.mit.edu/scsh/
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which points to the following file, retrievable by anonymous ftp:
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ftp://ftp-swiss.ai.mit.edu/pub/su/scsh/scsh.tar.gz
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The tar file includes full sources, a detailed manual and a paper
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describing 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 for your system by simply ftping
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the release file, and doing the following:
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gunzip < scsh.tar.gz | tar xf -
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cd scsh-0.5
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./configure
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make
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make install
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* New in this release
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---------------------
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Our last release had a lot of new code, and some elements were pretty
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flaky. Scsh is now much more robust. All known bugs have been fixed.
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Scsh now supports complete Posix, including signal handlers.
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Early autoreaping of child processes is now handled by a SIGCHLD
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signal handler, so children are reaped as early as possible with no
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user intervention required.
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A functional static heap linker is included in this release.
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It is ugly, limited in functionality, and extremely slow, but it works.
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It can be used to build scsh binaries that start up instantly.
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There is a new command-line switch,
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-sfd <num>
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which causes scsh to read its script from file descriptor <num>.
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Scheme 48's floating-point support was inadvertently omitted from the last
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release. It has been reinstated.
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The regular expression system has been sped up. Regular-expression
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compilation is now provided, and the AWK macro has been rewritten to
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pre-compile regexps used in rules outside the loop. It is still, however,
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slower than it should be.
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We have introduced two new procedures for performing regexp-directed
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string substitutions:
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regexp-substitute
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regexp-substitute/global
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The design differs from what one finds in systems such as sed or perl,
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and is quite powerful.
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Execing programs should be faster in this release, since we now use the
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CLOEXEC status bit to get automatic closing of unrevealed port file
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descriptors.
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* Thanks
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--------
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We received many bug reports, improvements, fixes and suggestions from scsh
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users. In particular, we'd like to thank Alan Bawden, Michael Becker, Jim
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Blandy, Jin Choi, Sean Doran, Lutz Euler, Kevin Esler, Rolf-Thomas Happe,
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David Hull, Shriram Krishnamurthi, Tod Olson, Michel Schinz, Bill Sommerfeld,
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Mike Sperber, and Victor Zandy for their contributions to this release.
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Thanks, guys; we really appreciate the feedback.
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Olin Shivers Brian D. Carlstrom
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Cambridge, Mass. Santa Clara, Ca.
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May, 1997
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