By Richard Kelsey and Jonathan Rees, html-ized and lightly edited by Margaret Fleck.
A line may take us hours, yet if it does not seem a moment's thought All our stitching and unstitching has been as nought. Yeats Adam's Curse
Scheme 48 is an implementation of the Scheme programming language as described in the The Revised^4 Report on the Algorithmic Language Scheme. It is based on a compiler and interpreter for a virtual Scheme machine. The name derives from our desire to have an implementation that is simple and lucid enough that it looks as if it were written in just 48 hours. We don't claim to have reached that stage yet; much more simplification is necessary.
Scheme 48 tries to be faithful to the upcoming Revised^5 Scheme Report, providing neither more nor less in the initial user environment. (This is not to say that more isn't available in other environments; see below.) Support for numbers is weak: bignums are slow and floating point is almost nonexistent (see description of floatnums, below). DEFINE-SYNTAX, LET-SYNTAX, LETREC-SYNTAX, and SYNTAX-RULES are supported, but not the rest of the Revised^4 Scheme macro proposal.
The Revised^5 Report hasn't been published yet, but it will be very similar to the Revised^4 Report. Likely differences were discussed at a 25 June 1992 meeting.
Scheme48 is maintained by Richard Kelsey. The latest version of scheme48 can be found on his home page .
This is what might be called an alpha release. Please report bugs, especially in the VM, especially core dumps, to email@example.com. Include the version number x.yy from the "Welcome to Scheme 48 x.yy" greeting message in your bug report. It is a goal of this project to produce a bullet-proof system; we want no bugs and, especially, no crashes. (There are a few known bugs, listed in the TODO file that comes with the distribution.)
Send mail to firstname.lastname@example.org to be put on a mailing list for announcements, discussion, bug reports, and bug fixes.
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