DESIGN AND IMPLEMENTATION OF AN LR (1) PARSER GENERATOR

Abstract

These days Computers are being used in highly diverse fields. New high level languages are cropping up at a very fast pace. To handle this situation it is important that language translators are developed quickly, . economically and with good validity guarantees., This is possible, only if the various translator writing tools are used to the fullest extent. Parser Generator is a software tool which accepts the syntactic specifications of a language and develops a framework for parsing the sentences of the language. The syntax of the language is described by context—free grammars. In this dissertation work one such Parser Generator has been designed . and implemented an DECSYSTEM-20 installed in the University-. This system generates parsing tables for LR(l) grammars. These tables can be used by a simple LR parsing routine to parse the sentences of the language. LR(l) grammars can describe the syntax of a very large class of languages. The system is modular. This makes it highly readable and modifiable. Each procedure used in the module can be separately compiled. System has been tested for a variety of grammars and results have been found satisfactory..