//This file is part of SECONDO.

//Copyright (C) 2004, University in Hagen, Department of Computer Science, 
//Database Systems for New Applications.

//SECONDO 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.

//SECONDO 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 SECONDO; if not, write to the Free Software
//Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package viewer.hoese.algebras;

import sj.lang.ListExpr;
import viewer.hoese.*;

public class Dsplrational extends DsplGeneric {
   // returns a string representing this rational or "ERROR" if
   // the format of the list is wrong
   private String getValueString(ListExpr value){
     int len = value.listLength();
     if(len!=4 && len !=5)
        return "ERROR";
     String result="";
     if(value.listLength()==5){ // with sign
        ListExpr SignList = value.first();
        if(SignList.atomType()!=ListExpr.SYMBOL_ATOM)
           return "ERROR";
        String sign = SignList.symbolValue();
        if(sign.equals("-")) // ignore other values
           result += sign +" ";
           value = value.rest(); // skip the signum
     }
     // check the types
     if( value.first().atomType()!=ListExpr.INT_ATOM ||
         value.second().atomType()!=ListExpr.INT_ATOM ||
         value.fourth().atomType()!=ListExpr.INT_ATOM)
         return "ERROR";
     int intPart = value.first().intValue();
     int numDecimal = value.second().intValue();
     int denomDecimal = value.fourth().intValue();
     result += ""+(denomDecimal*intPart+numDecimal) + " / " + denomDecimal;
     return result;
   }

 public void init (String name, int nameWidth, int indent, 
                   ListExpr type, ListExpr value, QueryResult qr)
  {
     String T = name;
     String V = getValueString(value);
     T=extendString(T,nameWidth, indent);
     qr.addEntry(T + " : " + V);
     return;
  }
}