FREE TEACHING TOOLS -- Grammars, Parsing and Generation (original) (raw)

School of Computer Science-- The University of Birmingham

In collaboration with The University of Sussex:
Informatics Departmentand Centre for Research in Cognitive Science

This is part of theFree Poplog Portal

Examples of teaching and demonstration materials

concerned with parsing and grammars for natural language This is part of the web site on learning to do 'Thinky' Programming http://www.cs.bham.ac.uk/research/projects/poplog/examples

NB
The files with the '.p' suffix include Pop-11 code and comments. They should be treated as plain text files. If your browser cannot read them that may be because it associated '.p' with another type of file. You may have to use the 'Open with' option in your web browser (usually via right click, depending on the browser.)
All of these examples can be run in the Pop-11 system that is part of Poplog, available for use in a virtual linux that runs on windows, macs, etc.here, or downloadable for installation in a linux systemhere.

CONTENTS

• This file: CONTENTS.html
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/grammar.txt
  An introduction (for absolute beginners) ideas of grammar, grammatical structures, lexicon, lexical types, grammar-based random generation of sentences, parsing of sentences.
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/grammarexamples
  Examples of things that can be done by learners after being introduced to the grammar formalism and the library designed for using the grammars to generate or parse sentences.
• NOT FOR NOVICES TO READ
  http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/grammar.p
  Lightly commented, Pop-11 source code for the LIB GRAMMAR package that makes all the above work. It depends on use of the Pop-11 matcher for list structures. [ADD LINK]
• NOT FOR NOVICES TO READ
  http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/newgrammar.p
  A modified version of Pop-11 LIB GRAMMAR to support use of an ill-formed substring table to speed up parsing (with spectacular results).
  This, like the original library, finds only one parse, even if the input string is ambiguous according to the grammar.
  To find where this differs from the original library look for occurrences of the global variable no_parse_found and calls of the proceduresetup_noparses();
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/robogram.p
  A grammar for an artificial subset of English relevant to a conversational robot.
  This shows how, using Pop-11's formalism for recursive context-free grammars, it is possible to define a fairly complex grammar for assertions, questions and commands, for the domain of a robot with the ability to perceive and manipulate objects on a table.
  (As in the CoSy and CogX robot projects at Birmingham.)
  Using the standard Pop-11 grammar library, parsing sentences of the sorts generated by this grammar can be very slow.
  Using newgrammar.p, with the ill-formed substring memory, speeds that up enormously. (The memory is cleared and rebuilt for each sentence. The program could be changed to create an enduring memory of things not to try.)
  This grammar was hand-coded, using an idea suggested long ago by Gerald Gazdar, namely compiling semantic categories into syntactic categories. In a more ambitious project it might be possible to make a system that can learn such a grammar by being exposed to a very large corpus of examples.
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/robolex.p
  A lexicon for use with the above grammar, i.e. words to be used in statements, commands, and questions referring to the robot and its environment and actions.
  This package has no understanding of inflections: different forms for the same word, depending on context of use. All words are treated as unanalysed wholes, except for the use of apostrophes.
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/robolang_demo.p
  Example code for compiling and testing the grammar and lexicon, using the tools in newgrammar.p
  This includes some examples that invoke the linux 'espeak' program to say the generated sentences out loud.
• http://www.cs.bham.ac.uk/research/projects/poplog/examples/robolang/test.p
  One test sentence parsed, to show the sort of parse tree produced. The sentence is
  [move the big red box on the tray onto the top of the block on the left side of Jeremy"s triangular horse]
  The parse tree is too big to be displayed easily, though it can be displayed in an xterm-compatible window, or using the poplog XVed editor.
  A screen-shot of the tree displayed in an xterm window with a small font is below,
  automatically generated by the Pop-11 'showtree' library package.
  This list may be extended.

Suggestions for improvement are welcome.

This file maintained by:Aaron Sloman
School of Computer Science, University of Birmingham
Installed: 13 Jun 2011
Last Updated: 14 Jun 2011

Aaron Sloman http://www.cs.bham.ac.uk/~axs