A compiled, type-safe, multi-stage programming language. MetaOCaml is a multi-stage extension of the OCaml programming language, and provides three basic constructs called Brackets, Escape, and Run for building, combining, and executing future-stage computations, respectively. (Please read README-META file in distribution for MetaOCaml's syntax for these constructs). MetaOCaml is a compiled dialect of MetaML. Download current (February 3nd, 2006) (or archived distributions) and follow instructions in INSTALL-META. For Windows, you'll need Cygwin Hot from the Press!: Science of Computer Programming special issue on MetaOCaml Learn more about multi-stage programming.
Stratego/XT is a language and toolset for constructing stand-alone program transformation systems. It combines the Stratego transformation language with the XT toolset of transformation components, providing a framework for constructing stand-alone program transformation systems. The Stratego language is based around a programming paradigm called strategic term rewriting. It provides rewrite rules for expressing basic transformation steps. The application of these rules can be controlled using strategies, a form of subroutines. The XT toolset provides reusable transformation components and declarative languages for deriving new components. Program transformations often operate by modifying the (AST). In Stratego it is also possible to specify transformations using concrete syntax. This allows programmers to express a transformation using the familiar (and often more concise) syntax of the object programming language, while it internally still operates on the AST.
One of the key goals of rewriting logic from its beginning has been to provide a semantic and logical framework in which many models of computation and languages can be naturally represented. There is by now very extensive evidence supporting the claim that rewriting logic is indeed a very flexible and simple logical and semantic framework. From a language design point of view the obvious question to ask is: how can a rewriting logic language best support logical and semantic framework applications, so that it becomes a metalanguage in which a very wide variety of logics and languages can be both semantically defined, and implemented? Our answer is: by being reflective. This paper discusses our latest language design and implementation work on Maude as a reflective metalanguage in which entire environments---including syntax definition, parsing, pretty printing, execution, and input/output---can be defined for a language or logic L of choice.