% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %
%                                                                           %
% File:            ordering.dtr                                             %
% Purpose:         ordered multiple inheritance                             %
% Author:          Gerald Gazdar, April 1991                                %
% Email:           geraldg@cogs.sussex.ac.uk                                %
% Address:         COGS, Sussex University, Brighton BN1 9QH, UK            %
% Documentation:   see item cited below                                     %
% Related files:   multiple.dtr                                             %
% Version:         1.21                                                     %
%                                                                           %
%      Copyright (c) University of Sussex 1991.  All rights reserved.       %
%                                                                           %
% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %

% Roger Evans, Gerald Gazdar, & Lionel Moser (1993) "Prioritised multiple
% inheritance in DATR" in Ted Briscoe, Valeria de Paiva & Ann Copestake,
% eds., Inheritance, Defaults, and the Lexicon, Cambridge, CUP, 38-46.

% Various researchers using default inheritance networks for lexical
% representation have wished to use a general form of multiple inheri-
% tance constrained by an explicit preference ordering on the parent nodes
% ("if you can get the info from node A, then do so, otherwise try node B,
% and if that fails, then take a look at node C").  Flickinger's 1987 PhD
% dissertation and the work of Russell, Warwick and their colleagues at
% ISSCO provide clear examples of this style of analysis.  This example
% shows how one can reconstruct analyses of this kind within DATR, despite
% the latter's commitment to an orthogonal form of inheritance.  See the
% file 'multiple.dtr' for another way of achieving the same end.

# vars  $item: ant bat cat dog eel fly gnu.

Idem:   <> == undef
        <undef> == <>
        <$item> == $item.

One:    <> == Idem
        <the axe> == ant
        <the bin> == bat
        <the can> == cat
        <the dot> == dog.

Two:    <> == Idem
        <the axe> == bat
        <the bin> == cat
        <the end> == fly
        <the fit> == gnu.

Three:  <> == Idem
        <the axe> == cat
        <the can> == eel
        <the end> == gnu
        <the gun> == ant.

T123:   <> == Idem
        <the> == <One Two Three>.
T231:   <> == Idem
        <the> == <Two Three One>.
T312:   <> == Idem
        <the> == <Three One Two>.
T132:   <> == Idem
        <the> == <One Three Two>.
T213:   <> == Idem
        <the> == <Two One Three>.
T321:   <> == Idem
        <the> == <Three Two One>.

%------ some theorems -------------------

% T123: <the axe> = ant
%       <the bin> = bat
%       <the can> = cat
%       <the dot> = dog
%       <the end> = fly
%       <the fit> = gnu
%       <the gun> = ant
%       <the hit> = undef.

% T213: <the axe> = bat
%       <the bin> = cat
%       <the can> = cat
%       <the dot> = dog
%       <the end> = fly
%       <the fit> = gnu
%       <the gun> = ant
%       <the hit> = undef.

% T312: <the axe> = cat
%       <the bin> = bat
%       <the can> = eel
%       <the dot> = dog
%       <the end> = gnu
%       <the fit> = gnu
%       <the gun> = ant
%       <the hit> = undef.

# hide  One Two Three Idem.

# show  <the axe>
        <the bin>
        <the can>
        <the dot>
        <the end>
        <the fit>
        <the gun>
        <the hit>.

% The next line is the Revision Control System Id: do not delete it.
% $Id: archive.dtr,v 1.1 1997/04/09 20:40:33 root Exp $