Racket is a general-purpose, multi-paradigm programming language and a multi-platform distribution that includes the Racket language, compiler, large standard library, IDE, development tools, and a set of additional languages including Typed Racket (a sister language of Racket with a static type-checker), Swindle, FrTime, Lazy Racket, R5RS & R6RS Scheme, Scribble, Datalog, Racklog, Algol 60 and several teaching languages.
The Racket language is a modern dialect of Lisp and a descendant of Scheme. It is designed as a platform for programming language design and implementation. In addition to the core Racket language, Racket is also used to refer to the family of programming languages and set of tools supporting development on and with Racket. Racket is also used for scripting, computer science education, and research.
The Racket platform provides an implementation of the Racket language (including a runtime system, libraries, and compiler supporting several compilation modes: machine code, machine-independent, interpreted, and JIT) along with the DrRacket integrated development environment (IDE) written in Racket. Racket is used by the ProgramByDesign outreach program, which aims to turn computer science into "an indispensable part of the liberal arts curriculum".
The core Racket language is known for its extensive macro system which enables creating embedded and domain-specific languages, language constructs such as classes or modules, and separate dialects of Racket with different semantics.
The platform distribution is free and open-source software distributed under the Apache 2.0 and MIT licenses. Extensions and packages written by the community may be uploaded to Racket's package catalog.
Matthias Felleisen founded PLT Inc. in the mid 1990s, first as a research group, soon after as a project dedicated to producing pedagogic materials for novice programmers (lectures, exercises/projects, software). In January 1995, the group decided to develop a pedagogic programming environment based on Scheme.