DrScheme: a programming environment for Scheme

Abstract

DrScheme is a programming environment for Scheme. It fully integrates a graphicsenriched editor, a parser for multiple variants of Scheme, a functional read-eval-print loop, and an algebraic printer. The environment is especially useful for students, because it has a tower of syntactically restricted variants of Scheme that are designed to catch typical student mistakes and explain them in terms the students understand. The environment is also useful for professional programmers, due to its sophisticated programming tools, such as the static debugger, and its advanced language features, such as units and mixins.Beyond the ordinary programming environment tools, DrScheme provides an algebraic stepper, a context-sensitive syntax checker, and a static debugger. The stepper reduces Scheme programs to values, according to the reduction semantics of Scheme. It is useful for explaining the semantics of linguistic facilities and for studying the behavior of small programs. The syntax checker annotates programs with font and color changes based on the syntactic structure of the program. On demand, it draws arrows that point from bound to binding occurrences of identifiers. It also supports α-renaming. Finally, the static debugger provides a type inference system that explains specific inferences in terms of a value-flow graph, selectively overlaid on the program text.

Embedding Dynamic Dataflow in a Call-by-Value Language

“…FrTime extends the language of DrScheme [9] with support for dynamic dataflow through a notion of signals, or time-varying values. The language is inspired and informed by work on functional reactive programming (FRP) [7,16,19], which extends Haskell [14] with similar features.…”

“…This paper describes FrTime (pronounced "father time"), a programming language built atop the DrScheme environment [9]. FrTime is an exploration of an important point in the design space of dynamic dataflow, or functional reactive [7,16,19], programming.…”

Implementation and use of the PLT scheme Web server

“…We have therefore explored an alternative framework for writing Web applications and report on our results in this paper. Specifically, we present the PLT Scheme Web Server [18], a server written in PLT Scheme [12] that uses first-class continuations to enable direct-style programming [10] for Web applications. In addition to describing the server, we present its use as an application platform through several illustrative examples, including a production-quality application for conference paper management called Continue.…”

Modeling an Algebraic Stepper

“…The most common ones are compilers, program analysis tools, debuggers, and profilers. Our DrScheme programming environment [9,8] also provides an algebraic stepper for Scheme. It explains a program's execution as a sequence of reduction steps based on the ordinary laws of algebra for the functional core [2,…”