Pictorial relationships -- a syntactic approach

Grammars or syntax specifications address themselves to the characterisation in symbolic terms of the structure of complex expressions. Two types of expression of empirical interest have been studied: sentences in English and other'natural' languages, and programs written in some high-level procedural language like ALGOL. Expressions in these languages consist of sets of elements (words and characters) coordinated with one another according to the sensorily manifest relationship'alongside', more commonly termed'followed by'.