Definition of programming languages using transformational semantics

Abstract

One method of implementing a high- level language is to translate programs written in it to an intermediate language and interpret the object programs in that intermediate language on the target machine . For an efficient implementation the design of the intermediate language will depend on both the high- level language and the target machine . The idea that an intermediate language suited to the high- level language and a particular target machine can be generated automatically from descriptions of that language and machine is introduced in this thesis. This requires an "interpreter generator" to produce, from the two descriptions , the high- level language compiler producing intermediate language code, and an interpreter for that intermediate language on the target machine . Such a system is discussed in an appendix . This thesis develops a method for describing a high-level language designed for use in the context of an interpreter generator. This method describes a given language by translating it to a target language with known semantics, that is, by transformational semantics . The translation is defined by a high- level programming lan uage desi ned for the purpose . The target language is not machine orien ed and this reduces the possibility of the description method affectin the perceived structure of the high- level language . Four example definitions , one of a subset of Pascal , are given in appendices . Emphasis is placed on designing a practical , rather than theoretical , high- level language description method . The proposed way in which the intermediate language might be extracted from such a description is outlined by a number of examples .