/* Copyright (C) 2000, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://cs.unibo.it/helm/.
 */

/******************************************************************************/
/*                                                                            */
/*                               PROJECT HELM                                 */
/*                                                                            */
/*                     Ferruccio Guidi <fguidi@cs.unibo.it>                   */
/*                                 23/05/2002                                 */
/*                                                                            */
/*                                                                            */
/******************************************************************************/

%{
%}
   %token    <string> ID STR
   %token    LC RC CM SC LP RP AT PC DL FS DQ EOF 
   %token    AND ATTR ATTRIB DIFF EQ FALSE FUN IN INTER NOT OR PAT REF REFOF
   %token    REL SELECT SUB SUPER TRUE UNION WHERE
   %left     DIFF
   %left     OR UNION
   %left     AND INTER
   %nonassoc NOT
   %start    qstr ref query
   %type     <string>              qstr      
   %type     <MathQL.resource_set> query   
%%
   qstr:
      | QT       { ""      }
      | STR qstr { $1 @ $2 }
   ;
   svar:
      | PC ID { $2 }
   ;
   rvar:
      | AT ID { $2 }
   ;
   vvar:
      | DL ID { $2 }
   ;
   val:
      | MCONCL    { MQMConclusion   }
      | CONCL     { MQConclusion    }
      | STR       { MQCons $1       } 
      | rvar      { MQStringRVar $1 }
      | svar      { MQStringSVar $1 }
      | func rvar { MQFunc ($1, $2) }
   ;
   boole:
      | TRUE            { MQTrue         }
      | FALSE           { MQFalse        }
      | str IS str      { MQIs ($1, $3)  }
      | NOT boole       { MQNot $2       }
      | boole AND boole { MQAnd ($1, $3) }
      | boole OR boole  { MQOr ($1, $3)  }
      | LPR boole RPR   { $2             }
   ;   
   rlist:
      | PATT REF                         { MQPattern $2          } 
      | rlist UNION rlist                { MQUnion ($1, $3)      }
      | rlist INTER rlist                { MQIntersect ($1, $3)  }
      | USE rlist POS svar               { MQUse ($2, $4)        }
      | USEDBY rlist POS svar            { MQUsedBy ($2, $4)     }
      | SELECT rvar IN rlist WHERE boole { MQSelect ($2, $4, $6) }
      | LPR rlist RPR                    { $2                    }
   ;
   query:
      rlist EOF { MQList $1 }
   ;