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From LL-regular to LL(1) grammars: Transformations, covers and parsing

Anton Nijholt
- 01 Jan 1982 - 
- Vol. 16, Iss: 4, pp 387-406
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TLDR
It is shown that it is possible to transform any LL-regular grammar G into an LL(1) grammar G' in such a way that parsing G' is as good as parsing G.
Abstract
In this paper it is shown that it is possible to transform any LL-regular grammar G into an LL(1) grammar G' in such a way that parsing G' is as good as parsing G. That is, a parse of a sentence of grammar G can be obtained with a simple string homomorphism from the parse of a corresponding sentence of G'. Since any LL(k) grammar is an LL-regular grammar the results that are obtained are valid for LL(k) grammars as well. The relation between LL-regular grammars is expressed by means of a generalized version of the well-known cover relation between two grammars.

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Citations
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Journal ArticleDOI

On the relation between context-free grammars and parsing expression grammars

TL;DR: A new formalism for CFGs is presented that borrows from PEGs the use of parsing expressions and the recognition-based semantics, and it is shown how one way of removing non-determinism from this formalism yields a formalism with the semantics of P EGs.
Journal ArticleDOI

Look-ahead pushdowns

TL;DR: The general notion of look-ahead on pushdowns is used to prove that the deterministic iterated pushdown languages are closed under complementation, and it is decidable whether an iterated indexed grammar is LL ( k ).
Journal ArticleDOI

The equivalence problem for LL- and LR-regular grammars☆

TL;DR: It is shown that the equivalence problem for LL-regular grammars is decidable by reducing it to the equivalences problem for real-time strict deterministic Grammars.
Book ChapterDOI

The Equivalence Problem for LL- and LR-Regular Grammars

TL;DR: It is shown that the equivalence problem for LL-regular grammars is decidable by reducing it to the equivalences problem for real-time strict deterministic Grammars.
References
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Book

The Theory of Parsing, Translation, and Compiling

TL;DR: It is the hope that the algorithms and concepts presented in this book will survive the next generation of computers and programming languages, and that at least some of them will be applicable to fields other than compiler writing.
Book

Formal Languages and Their Relation to Automata

TL;DR: The theory of formal languages as a coherent theory is presented and its relationship to automata theory is made explicit, including the Turing machine and certain advanced topics in language theory.
Book

Introduction to formal language theory

TL;DR: This volume intended to serve as a text for upper undergraduate and graduate level students and special emphasis is given to the role of algebraic techniques in formal language theory through a chapter devoted to the fixed point approach to the analysis of context-free languages.
Book

Context-Free Grammars: Covers, Normal Forms, and Parsing

Anton Nijholt
TL;DR: This monograph develops a theory of grammatical covers, normal forms and parsing by introducing algorithms that describe a transformation of an input grammar into an output grammar which satisfies the requirements.
Journal ArticleDOI

On the Covering and Reduction Problems for Context-Free Grammars

TL;DR: A formal definition of one grammar "covering" another grammar is presented and it is argued that this definition has the property that G' covers G when and only when the ability to parse G suffices for parsing G.