Discussion of Technical Aspects of Compiler Generation

While in Chaps. 2 and 3 we mainly wanted to present ideas, our aim is now to discuss ideas. We shall discuss a few selected, but basic, technical problems which are relevant to the compiler generator constructor. They are: (1) To what extent can compilation be expressed by homomorphisms, and to what extent can algebra be of help to compiler generator constructors? (2) What is a good semantic language? (3) Interface problems: in the big gap between a realistic source language and a realistic target language, what should be filled in by the compiler generator and what should be filled in by its user?