LINGUIST List 4.7

Mon 11 Jan 1993

FYI: ALE Program, Minimal Pairs File

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Directory

1. Carpenter, for Linguist -- ALE Program Available
2. The Linguist List, Minimal Pairs

ALE: An Attribute Logic Engine
-------------------------------

ALE, a public domain system written in Prolog, integrates phrase
structure parsing and constraint logic programming with typed feature
structures as terms. This generalizes both the feature structures of
PATR-II and the terms of Prolog II to allow type inheritance and
appropriateness specifications for features and values. Grammars may
also interleave unification steps with logic program goal calls (as
can be done in DCGs), thus allowing parsing to be interleaved with
other system components. While ALE was developed to handle HPSG
grammars, it can also execute PATR-II grammars, DCG grammars, Prolog,
Prolog-II, and LOGIN programs, etc.

Grammars and logic programs are specified using a typed version of
Rounds-Kasper attribute-value logic, which includes variables and full
disjunction. Programs are then compiled into low-level Prolog
instructions corresponding to the basic operations of the typed
Rounds-Kapser logic. There is a strong type discipline enforced on
descriptions, allowing many errors to be detected at compile-time.

The logic programming and parsing systems may be used independently or
together. Features of the logic programming system include negation,
disjunction and cuts. It has last call optimization, but does not
perform any argument indexing. On the 'naive reverse' benchmark, it
performed at 1000 LI/s on a DEC 5100 running SICStus 2.1, which is
rouglhy 15% as fast as the SICStus interpreter and 1.5% as fast as the
SICStus compiler.

The phrase structure system employs a bottom-up all-paths chart
parser. A general lexical rule component is provided, including
procedural attachment and general methods for orthographic
transformations using pattern matching or Prolog. Empty categories
are permitted in the grammar. Both the phrase structure and logic
programming components of the system allow parametric macros to be
defined and freely employed in descriptions. Parser performance is
similar to that of the logic programming system. In an early HPSG
grammar, where feature structures consisted of roughly 100-200 nodes
each, a 10 word sentence producing 25 completed inactive edges parsed
in roughly two seconds, using SICStus 2.1 on a DEC 5100.

Complete documentation (running to 80 pages, with examples of everything,
programming advice, and sample grammars), is available as:

 Bob Carpenter (1992) ALE User's Guide. Carnegie Mellon University
 Laboratory for Computational Linguistics Technical Report.
 Pittsburgh.

ALE can be run in either SICStus or Quintus Prolog, and with other
compatible compilers doing first-argument indexing and last-call
optimization. The system and its documentation are available without
charge for research purposes from the address below. Please indicate
whether electronic copies of program and documentation can be sent via
e-mail and whether they should be compressed or not:

 full compressed.Z
 Documentation LaTeX 150k 61k
 .dvi 200k 93k
 PostScript 530k 236k
 Program ALE 85k 28k
 grammars 10k 4k

Otherwise, documentation can be sent out by hard mail. Tape or disk
copies of the system might be possible if absolutely necessary.

The full theoretical details behind ALE are available in the book:

 Bob Carpenter (1992) _The Logic of Typed Feature Structures with
 Applications to Unification Grammars, Logic Programs and
 Constraint Resolution_. Cambridge Tracts in Theoretical
 Computer Science 32, Cambridge University Press.

 Ordering Information
 US: CUP, 110 Midland Ave, Port Chester, NY 10573-4930,
 800-872-7423 (about 35 dollars US)
 Europe: 20 pounds UK, CUP, Edinburgh Bldg, Shaftesbury Rd,
 Cambridge CB2 2RU UK (about 20 pounds UK)]

This book covers many details which are not included in the system,
including inequations, extensionality and general constraint
resolution. It also details the completeness results for the
description languages. A future version of ALE should be available by
Summer 1993 which contains a full implementation of everything in this
book.

- Bob Carpenter
 Computational Linguistics Program
 Philosophy Department
 Carnegie Mellon University
 Pittsburgh, PA 15213
 Net: carplcl.cmu.edu
 Phone: (412) 268-8573 Fax: (412) 268-1440

When the following message was posted, we neglected to mention
how the file mentioned in it could be obtained. To get that file
from the Listserv, send the message:

get minimal txt linguist

to the address:

listservtamvm1.tamu.edu (if you're on Internet)

 or:

listservtamvm1 (if you're on Bitnet)
 ------******------

> Date: Mon, 4 Jan 93 14:37:20 GMT
> From: "J.J. Higgins - Education" <J.Higginsbristol.ac.uk>
> Subject: Re: Minimal pairs

> Homophones and minimal pairs in English; how many are there?

> Members of LINGUIST may be interested in a program I have written to
> extract homophones and minimal pairs from an electronic dictionary. The
> source is the version of the Advanced Learners' Dictionary deposited by
> Roger Mitton in the Oxford Text Archive. The program sorts the
> pronunciation field and flags all homophones. It then replaces two
> characters in the pronunciation field with the same dummy character and
> sees how many additional homophones this creates.

> I have deposited on the LISTSERV a brief description of the project and the
> lists for FEET/FIT, HAD/HEAD, PULL/POOL, BAN/PAN, FAN/VAN, THIN/TIN,
> THY/THIGH, LOCK/ROCK, and homophones. I welcome suggestions as to which of
> the 491 potential lists I should tackle next.

> Apologies to TESL-L subscribers who may have seen most of this before.

> Happy 1993!

> John Higgins, School of Education, University of Bristol
> J.Higginsbristol.ac.uk