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%                                                                           %
% File:            fscons.dtr                                               %
% Purpose:         construction of feature structures with a DATR lexicon   %
%                  using type definitions and special DATR nodes for PROLOG %
%                  notation of feature structures                           %
% Author:          James Kilbury, 5 August 1994                             %
% Email:           kilbury@ling.uni-duesseldorf.de                          %
% Address:         U Drf, Universitaetsstr. 1, D-40225 Duesseldorf, Germany %
% Version:         1.02                                                     %
% Related files:   englex1.dtr, fsctest.dtr                                 %
%                                                                           %
%      Copyright (c) University of Duesseldorf 1994.  All rights reserved.  %
%                                                                           %
% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %

% See James Kilbury / Petra Naerger [Barg] / Ingrid Renz (1991)
%     DATR as a Lexical Component for PATR, pp. 137-142,
%     Proceedings of the 5th Conference of the European ACL Chapter

% The symbols '[', ']', ':', and ',' are PROLOG connectives for the
% representation of feature structures.    The advantage of the technique
% employed in this DATR theory lies precisely in that fact that the
% syntax of these symbols is stated once in language-independent DATR
% code so that it need not be repeated in the formulation of particular
% DATR lexica.

FS:
    <$A> == '['  SPECIF  SP_REST:<>  ']' .   % feature structure

SPECIF:
    <$A> == $A  ':'  "< PATH >" .            % specification

SP_REST:
    <+>  ==                                  % termination (junk cut-off)
    <$A> == ','  SPECIF  <> .                % recursion

 
PATH:
    <$A> == PATH_PREFIX:<>  $A  *  + .       % '*' as 2nd stack marker
                                             %  for end of relevant path;
                                             % '+' cuts off inherited junk
 
PATH_PREFIX:
    <+>  == PATH_TO_SEQUENCE:<>
    <$A> == <>.                              % shorten path by one

T:
    <> == +  PATH_TO_SEQUENCE .              % tail of the path
                                             % '+' as 1st stack marker

PATH_TO_SEQUENCE:
    <>   ==                                  % empty path
    <*>  ==                                  % termination (end of path)
    <+>  ==                                  % termination (junk cut-off)
    <$A> == $A  <> .                         % recursion

LIST:
    <> == FS:<fi re T +>.                    % lists with fi(rst)
                                             %        and re(st) 

% 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 $