Chez Scheme

Chez Scheme
Paradigms	Multi-paradigm: functional, imperative, meta
Family	Lisp
Designed by	R. Kent Dybvig
Developer	Cadence Research Systems
First appeared	1985; 36 years ago
Stable release	9.5.4 / August 30, 2020; 12 months ago
Typing discipline	Dynamic, latent, strong
Scope	Lexical
Platform	x86 (IA-32, x86-64) PowerPC, SPARC, ARMv6
OS	Cross-platform
License	Apache License 2.0
Filename extensions	.ss
Website	www.scheme.com
Influenced by
	Lisp, Scheme

Chez Scheme is a programming language, a dialect and implementation of the language Scheme which is a type of Lisp. It uses an incremental native-code compiler to produce native binary files for the x86 (IA-32, x86-64), PowerPC, and SPARC processor architectures. It has supported the R6RS standard since version 7.9.1.^[2] It is free and open-source software released under an Apache License, version 2.0. It was first released in 1985, by R. Kent Dybvig, originally licensed as proprietary software, and then released as open-source software on GitHub on 2016-05-13 with version 9.4.^[3]

Petite Chez Scheme is its sibling implementation which uses a threaded interpreter design instead of Chez Scheme's incremental native-code compiler. Programs written for Chez Scheme run unchanged in Petite Chez Scheme, as long as they do not depend on using the compiler (for example foreign function interface is only available in the compiler). Petite Chez Scheme is freely distributable and may be used with no royalty fees, subject to the license agreement.^[4]

History[]

The first version of Chez Scheme was developed by R. Kent Dybvig and completed in 1984.^[5] Some copies of the original version were distributed in 1985.

Cadence Research Systems developed Chez Scheme until the company was purchased by Cisco Systems in 2011.^[6] Cisco open-sourced Chez Scheme in 2016.^[7]

Performance[]

In one series of benchmarks,^[8] Chez Scheme was among the fastest available Scheme implementations on the Sun SPARC processor architecture, while Petite Chez Scheme was among the slowest implementations on the more common x86 (Pentium 32-bit) processor architecture.

Libraries[]

Chez Scheme has a windowing system and computer graphics package called the Scheme Widget Library, and is supported by the portable SLIB library.^{[citation needed]}. However the widget library is no longer maintained.^[9]