/* @(#)README 24.1 4/13/88 */

This README file is a simple description about how to run the programs in this directory. Read BENCH.DOC for a better description.

To run chat:

| ?- compile(chat). ....... | ?- demo(mini). % Runs a small set of demo questions | ?- demo(main). % Runs a larger set of demo questions | ?- test_chat. % Runs the large set of demo questions % and produces a table of statistics

or you can run chat interactively by giving the goal | ?- hi. % prompts for questions then gives you the prompt

Question:

Chat is now expecting a question. E.g.

Question: where is France?

Capital letters are not distinguished from lower case. If Chat does not understand a word it prompts you to re-type it (or a synonym for it). This word must be terminated with a period.

Apart from questions, the following directives are accepted by Chat:

Question: bye.                  (exits back to the Prolog top level)

Question: trace.                (turns on Chat's tracing mechanism)
Question: do not trace.         (turns off the tracing mechanism)
Question: do mini demo.         (calls demo(mini))
Question: do main demo.         (calls demo(main))
Question: test chat.            (calls test_chat)

The various files which make up the program Chat-80
===================================================

---

Copyright (C) 1982

David Warren,

SRI International, 333 Ravenswood Ave., Menlo Park,

California 94025, USA;

Fernando Pereira,

Dept. of Architecture, University of Edinburgh,

20 Chambers St., Edinburgh EH1 1JZ, Scotland

This program may be used and distributed in accordance with

the file LICENSE.txt included in this distribution.

_________________________________________________________________________

File Purpose ==== =======

chat.pl Compile this file to get a compiled Chat-80, interpret it to get an interpreted Chat-80.

clone.xg lex.xg The XG which defines the syntax accepted by Chat-80

clotab.pl Table of normal form modifier attachments

xgproc.pl This is a preprocessor to translate XGs into Prolog. If needed, it should be compiled separately. It defines the following evaluable predicates:-

+ File :	reads in File treating any grammar rules
                in it as XG rules;
list(File) :	writes out to File the Prolog clauses for
                the XG files read in so far.

xgrun.pl Defines the run time support predicates for XGs (see XGs paper).

newg.pl The Chat-80 grammar after preprocessing. It was obtained by typing the following:-

prolog
[xgproc].
+ 'clone.xg'.
+ 'lex.xg'.
list('newg.pl').

newdic.pl The syntactic dictionary. It defines both application-independent and application-dependent (world database) words.

slots.pl Determines what modifies what.

scopes.pl Determines the scopes of determiners and other operators, and produces an unsimplified query.

templa.pl Defines the meaning of the application-dependent words.

qplan.pl Optimises a simplified query.

talkr.pl Executes queries.

ndtabl.pl

Gives statistical information about the predicates in the world
database (and also some application-independent ones such as
'average'). This is used by the query optimiser.

A clause in ndtabl.pl has the form

nd(Predicate,PredSize,Dom1Size,...,DomkSize).

Predicate is the name of a database predicate of arity k.

PredSize, Dom1Size, ..., DomKSize measure the sizes of the
the predicate (number of solutions) and the sizes of the domains
for each argument (the number of distict values that argument
may take in a call to the predicate). we use a logarithmic
size measure

        s = 10 * log10(n)

where n is the actual size (number of solutions or number pf
distinct values) of a predicate or argument domain.

Thus

        nd(flows,19,16,22)

indicates that the binary predicate "flows" has around 80
solutions, and it is going to be called with its first
argument taken from a set with around 40 elements (number
of rivers in the database) and its second argument taken
from a set with around 158 elements (number of countries
in the database).

readin.pl Reads in sentences.

ptree.pl Prints out parse trees.

aggreg.pl Executes set operators such as 'average'.

world0.pl rivers.pl cities.pl countr.pl contai.pl border.pl The world database.

chattop.pl Top level of Chat-80 and query simplifier. demo Sample queries. To run in batch mode, type

hi(demo)

to the Prolog toplevel after loading Chat-80. log Output expected from `hi(demo).'