A*: a language for implementing language processors

A* is an experimental language designed to facilitate the creation of language-processing tools. It is analogous either to an interpreted yacc with Awk as its statement language, or to a version of Awk which processes programs rather than records. A* offers two principal advantages over the combination of lex, yacc, and C: a high-level interpreted base language and built-in parse tree construction. A* programmers are thus able to accomplish many useful tasks with little code. This paper describes the motivation for A*, its design, and its evolution. Experience with A* is described, and then the paper concludes with an analysis of that experience.<>