LR(1) Syntax Analysis

Theoretical studies of the properties of programming language grammars and of algorithms for syntax analysis have always been partly motivated by the search for a truly automatic means of constructing a syntax analyser. In the early 1960s so called ‘compiler-compilers’ were popular. One of the earliest was developed at the University of Manchester (Brooker et al., 1963): it included a parser-transcriber which took a syntax description and without alteration transcribed it into a top-down syntax analyser1. Foster’s SID (Foster,1968) was the first of many parser-generator programs which went further so far as syntax analysis was concerned: its input was a type 2 grammar, on which it performed most of the operations discussed in chapter 16 to produce a one-symbol-look-ahead grammar, which it finally transcribed into an ALGOL 60 program. The transformations required to make a grammar one-track or one-symbol-look-ahead aren’t always simply mechanical, however, and in practice a top-down parser-generator like SID often fails to complete its task. Parser-generators for top-down analysers were little used, therefore, and most syntax analysers were written by hand using the techniques discussed in earlier chapters.