Doctor of Philosophy

dissertationI present the design of a parser that adds Scheme-style language extensibility to languages with implicitly delimited and infix syntax. A key element of my design is an enforestation parsing step, which converts a flat stream of tokens into an S-expression-like tree, in addition to the initial "read" phase of parsing and interleaved with the "macro-expand" phase. My parser uses standard lexical scoping rules to communicate syntactic extensions to the parser. In this way extensions naturally compose locally as well as through module boundaries. I argue that this style of communication is better suited towards a useful extension system than tools not directly integrated with the compiler. This dissertation explores the limits of this design in a new language called Honu. I use the extensiblity provided by Honu to develop useful language extensions such as LINQ and a parser generator. I also demonstrate the generality of the parsing techniques by applying them to Java and Python

Extensible type systems

poste

Precise garbage collection for C

Journal ArticleMagpie is a source-to-source transformation for C programs that enables precise garbage collection, where precise means that integers are not confused with pointers, and the liveness of a pointer is apparent at the source level. Precise GC is primarily useful for long-running programs and programs that interact with untrusted components. In particular, we have successfully deployed precise GC in the C implementation of a language run-time system that was originally designed to use conservative GC. We also report on our experience in transforming parts of the Linux kernel to use precise GC instead of manual memory management

Run Your Research: On the Effectiveness of Lightweight Mechanization

Formal models serve in many roles in the programming language community. In its primary role, a model communicates the idea of a language design; the architecture of a language tool; or the essence of a program analysis. No matter which role it plays, however, a faulty model doesn\u27t serve its purpose. One way to eliminate flaws from a model is to write it down in a mechanized formal language. It is then possible to state theorems about the model, to prove them, and to check the proofs. Over the past nine years, PLT has developed and explored a lightweight version of this approach, dubbed Redex. In a nutshell, Redex is a domain-specific language for semantic models that is embedded in the Racket programming language. The effort of creating a model in Redex is often no more burdensome than typesetting it with LaTeX; the difference is that Redex comes with tools for the semantics engineering life cycle