Control Flow Imperative Expressions Block Structure

This paper presents a modular and extensible style of language speciication based on meta-computations. This style uses two monads to factor the static and dynamic parts of the speci-cation, thereby staging the speciication and achieving strong binding-time separation. Because metacomputations are deened in terms of monads, they can be constructed modularly and ex-tensibly using monad transformers. A number of language constructs are speciied: expressions, control-ow, imperative features, block structure, and higher-order functions and recursive bindings. Metacomputation-style speciication lends itself to semantics-directed compilation, which we demonstrate by creating a modular compiler for a higher-order, imperative, Algol-like language.