The Schism homepage

Welcome to the Schism homepage!

Schism is a partial evaluator for a pure (side effect free) subset of Scheme, written primarily by Charles Consel.

The main features of Schism are:

• Polyvariant binding-time analysis (BTA).
• Treatment of higher-order functions and partially static data structures.
• Colored binding-time information based on GNU emacs (19.30 or later).
• Binding-time inspector.

A bit of history

As with any non-trivial system, Schism has a history that has shaped the way the system is today. Schism has been developed by many people over time, including Michael Ashley, Charles Consel, Luke Hornof, Siau Cheng Khoo, Julia Lawall, and Barbara Moura.

• Schism is based on a 1987 partial evaluator named Skipe. This system treated a pure, first-order applicative language.
• This language was extended with data structures in the fall of 1989 as part of Charles Consel's PhD studies. Also, Skipe was ported to the language T, a Scheme-like language, and extended with higher-order functions. It was based on a higher-order, monovariant BTA described in a LFP'90 article. This BTA was later made polyvariant as reported in a PEPM'93 paper. An overall description of Schism was presented in another PEPM'93 paper.
• In 1992 Michael Ashley ported Schism to Chez Scheme(tm), a commercial implementation of an extended version of R4RS Scheme. Part of this work was done by implementing the syntax and functions from T that are missing in Chez Scheme. An improved BTA was included in this new version of Schism.
• It was decided in 1994 to make Schism available on platforms other than Chez Scheme in order to broaden its potential users. Although Schism has now been used by various researchers for a variety of applications, a broader distribution should allow us to improve it further and validate design choices.

To get Schism

New version 29th of April 1997

Click on schism-010.tar.gz (160 KB) to download it. The difference is small, so you might prefer this schism-009-010 patch (23 KB), if you have the old version. The manual is available as a PostScript (68 KB) file or as dvi (27 KB).

Schism requires an R4RS Scheme and the SLIB library. So far, Schism has only been tested with Chez Scheme and SCM, and Scheme48.

Bugs

Please report bugs to schism-bugs@irisa.fr.