To the author's knowledge three other operational compiler-compiler systems, whose strategy is similar to the scheme documented here, have been developed. The Feldman system [6, 7, 8] is a bounded context, syntax directed system. Syntax specifications are expressed in Floyd production language (FPL) and semantics are defined in Feldman semantic language (FSL). FSL seems to be a good model on which to base semantic languages. A lexical analysis (subscan to distinguish identifiers, operators, delimiters and punctuation marks) precedes the full analysis. In the COGENT system [5], on the other hand, each character is interpreted separately, hence allowing greater flexibility (e.g. its use in a symbolic differentiation program) and enforcing more detailed attention to syntax. Syntax for a source program is virtually in Backus Normal Form (BNF) [3] and this system is syntax directed along the lines suggested by Irons [1]. Much has been written on the compiler-compiler system of Brooker and Morris [2, 22, 23] which has superficial similarities with the COGENT scheme and the system described below.