The barrel concept: a study in language system development

We describe a variation in theme on abstract machine implementation through general purpose macro processing. Using data flow diagrams we show how the central focus of concern can be shifted from the output focus of conventional macro processing to an user-oriented focus, on a system developed upon an optimized and extended version of the Stage2 processor of W. Waite and co-workers.The approach has potential theoretical interest in its: being a modern expression of widely accepted older ideas and implementations, applications which incorporate synergisms in language concepts (string and list processing, tables), possible opening to logic programming.Data flow descriptions are used to illustrate top-level and selected lower level computation activities, e.g., combination evaluation. Usage of the array of capabilities presented by Barrel are outlined: portability, prototyping in a multiple-machine context, "permanent" (compiled) codes for network operations.