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Generalized LR Parsing

  • Masaru Tomita
Book

Table of contents

  1. Front Matter
    Pages i-xiii
  2. Masaru Tomita, See-Kiong Ng
    Pages 1-16
  3. Patrick Shann
    Pages 17-34
  4. James R. Kipps
    Pages 43-59
  5. Rahman Nozohoor-Farshi
    Pages 61-75
  6. Hozumi Tanaka, Hiroaki Numazaki
    Pages 77-91
  7. Keh-Yih Su, Jong-Nae Wang, Mei-Hui Su, Jing-Shin Chang
    Pages 93-112
  8. J. H. Wright, E. N. Wrigley
    Pages 113-128
  9. Stuart Malone, Sue Felshin
    Pages 129-139
  10. Hiroaki Saito, Masaru Tomita
    Pages 141-151
  11. Kenji Kita, Takeshi Kawabata, Hiroaki Saito
    Pages 153-164
  12. Back Matter
    Pages 165-166

About this book

Introduction

The Generalized LR parsing algorithm (some call it "Tomita's algorithm") was originally developed in 1985 as a part of my Ph.D thesis at Carnegie Mellon University. When I was a graduate student at CMU, I tried to build a couple of natural language systems based on existing parsing methods. Their parsing speed, however, always bothered me. I sometimes wondered whether it was ever possible to build a natural language parser that could parse reasonably long sentences in a reasonable time without help from large mainframe machines. At the same time, I was always amazed by the speed of programming language compilers, because they can parse very long sentences (i.e., programs) very quickly even on workstations. There are two reasons. First, programming languages are considerably simpler than natural languages. And secondly, they have very efficient parsing methods, most notably LR. The LR parsing algorithm first precompiles a grammar into an LR parsing table, and at the actual parsing time, it performs shift-reduce parsing guided deterministically by the parsing table. So, the key to the LR efficiency is the grammar precompilation; something that had never been tried for natural languages in 1985. Of course, there was a good reason why LR had never been applied for natural languages; it was simply impossible. If your context-free grammar is sufficiently more complex than programming languages, its LR parsing table will have multiple actions, and deterministic parsing will be no longer possible.

Keywords

Parsing algorithms complexity grammar hidden markov model logic programming natural language programming programming language

Editors and affiliations

  • Masaru Tomita
    • 1
  1. 1.Carnegie Mellon UniversityUSA

Bibliographic information

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