Historical background

The Revised6 Report on the Algorithmic Language Scheme (R6RS for short) is the sixth of the Revised Reports on Scheme.

The first description of Scheme was written by Gerald Jay Sussman and Guy Lewis Steele Jr. in 1975 [39]. A revised report by Steele and Sussman [38] appeared in 1978 and described the evolution of the language as its MIT implementation was upgraded to support an innovative compiler [36]. Three distinct projects began in 1981 and 1982 to use variants of Scheme for courses at MIT, Yale, and Indiana University [272512]. An introductory computer science textbook using Scheme was published in 1984 [1]. A number of textbooks describing and using Scheme have been published since [8].

As Scheme became more widespread, local dialects began to diverge until students and researchers occasionally found it difficult to understand code written at other sites. Fifteen representatives of the major implementations of Scheme therefore met in October 1984 to work toward a better and more widely accepted standard for Scheme. Participating in this workshop were Hal Abelson, Norman Adams, David Bartley, Gary Brooks, William Clinger, Daniel Friedman, Robert Halstead, Chris Hanson, Christopher Haynes, Eugene Kohlbecker, Don Oxley, Jonathan Rees, Guillermo Rozas, Gerald Jay Sussman, and Mitchell Wand. Their report [3], edited by Will Clinger, was published at MIT and Indiana University in the summer of 1985. Further revision took place in the spring of 1986 [4] (edited by Jonathan Rees and Will Clinger), and in the spring of 1988 [5] (also edited by Will Clinger and Jonathan Rees). Another revision published in 1998, edited by Richard Kelsey, Will Clinger and Jonathan Rees, reflected further revisions agreed upon in a meeting at Xerox PARC in June 1992 [21].

Attendees of the Scheme Workshop in Pittsburgh in October 2002 formed a Strategy Committee to discuss a process for producing new revisions of the report. The strategy committee drafted a charter for Scheme standardization. This charter, together with a process for selecting editorial committees for producing new revisions of the report, was confirmed by the attendees of the Scheme Workshop in Boston in November 2003. Subsequently, a Steering Committee according to the charter was selected, consisting of Alan Bawden, Guy L. Steele Jr., and Mitch Wand. An editors' committee charged with producing a new revision of the report was also formed at the end of 2003, consisting of Will Clinger, R. Kent Dybvig, Marc Feeley, Matthew Flatt, Richard Kelsey, Manuel Serrano, and Mike Sperber, with Marc Feeley acting as Editor-in-Chief. Richard Kelsey resigned from the committee in April 2005, and was replaced by Anton van Straaten. Marc Feeley and Manuel Serrano resigned from the committee in January 2006. Subsequently, the charter was revised to reduce the size of the editors' committee to five and to replace the office of Editor-in-Chief by a Chair and a Project Editor [29]. R. Kent Dybvig served as Chair, and Mike Sperber served as Project Editor. Will Clinger resigned from the committee in May 2007. Parts of the report were posted as Scheme Requests for Implementation (SRFIs, see http://srfi.schemers.org/) and discussed by the community before being revised and finalized for the report [1426139]. Jacob Matthews and Robby Findler wrote the operational semantics for the language core, based on an earlier semantics for the language of the “Revised5 Report” [24].