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Scheme is a LISP dialect introduced in 1975 that cuts down the language considerably but at the same time adds some functional features. The most popular variant of LISP for a while as it was much simpler to implement than full LISP or the later Common Lisp but its popularity has waned considerably.

There is also yet another schism happening in the Scheme world, most modern versions and all OS/2 version of Scheme follow the Revised(5) Report on the Algorithmic Language Scheme or the older but largely identical Revised(4), but a new Revised(6) standard from 2007 that introduces a number of incompatibilities has got a part of the Scheme community in a knot, meaning that some Scheme implementations aim at R(6) compatibility while others have declared that they will not use R(6) and continue developing from the R(5) standard.


The newest Revised(7) standard partly aims merging the R5R and R6R to a degree, the R7RS-small standard was published in 2013 and describes a subset of the language that mostly maintains the R5R semantics but takes the record types, libraries and exception handling form R6R. The full standard is still being worked on.

The only formal standard for Scheme, largely ignored.
Note, this standard is quite incompatible with Revised(5) in places and therefore not widely used.

OS/2 Implementations



DOS Implementations

  • Texas Instruments PC SCHEME - Commercial


  • Nils M. Holm: Sketchy LISP - 2009 - Public domain Scheme tutorial