PrologOperatorsContext.java

/* 
** Author(s): Miguel Calejo
** Contact:   interprolog@declarativa.com, http://www.declarativa.com
** Copyright (C) Declarativa, Portugal, 2000-2002
** Use and distribution, without any warranties, under the terms of the 
** GNU Library General Public License, readable in http://www.fsf.org/copyleft/lgpl.html
*/

package com.declarativa.interprolog;
import java.util.*;
import com.declarativa.interprolog.util.*;

public class PrologOperatorsContext {
        Hashtable prefixOperators,postfixOperators,infixOperators;
        boolean prefixOperator(Object node){
                return prefixOperators.containsKey(node);
        }
        boolean postfixOperator(Object node){
                return postfixOperators.containsKey(node);
        }
        boolean infixOperator(Object node){
                return infixOperators.containsKey(node);
        }
        PrologOperatorsContext(PrologOperator[] operators){
                int nOperators=0;
                if (operators!=null) nOperators=operators.length;
                prefixOperators = new Hashtable(nOperators+1);
                postfixOperators = new Hashtable(nOperators+1);
                infixOperators = new Hashtable(nOperators+1);
                for (int o=0;o<nOperators;o++){
                        int type=operators[o].type;
                        Hashtable placeholder = null;
                        if (type==fx||type==fy) 
                                placeholder=prefixOperators;
                        else if (type==xfx||type==xfy||type==yfx) 
                                placeholder=infixOperators;
                        else if (type==xf||type==yf)
                                placeholder=postfixOperators;
                        placeholder.put(operators[o].name,operators[o]);
                }
        }
        PrologOperatorsContext(){
                this(standardXSBOperators);
        }
        static final int xfx=1,xfy=2,yfx=3,fx=4,fy=5,xf=6,yf=7;
        static final PrologOperator[] standardXSBOperators={
                //current_op(P,T,Name), write(prologOperator(P,T,Name)), nl, fail. ...
                new PrologOperator(1200,xfx,":-"),
                new PrologOperator(1200,xfx,"-->"),
                new PrologOperator(1200,fx,"?-"), 
                new PrologOperator(1198,xfx,"::-"), 
                new PrologOperator(1150,fx,"hilog"),
                new PrologOperator(1150,fx,"dynamic"),new PrologOperator(1150,fx,"multifile"),
                new PrologOperator(1100,xfy,";"),
                new PrologOperator(1100,fx,"table"),
                new PrologOperator(1100,fx,"edb"),
                new PrologOperator(1100,fy,"index"),
                new PrologOperator(1100,fy,"ti"), 
                new PrologOperator(1100,fy,"ti_off"),
                new PrologOperator(1100,fx,"mode"),
                new PrologOperator(1100,fx,"export"),
                new PrologOperator(1100,fx,"parallel"),
                new PrologOperator(1100,fx,"local"),
                new PrologOperator(1050,fy,"import"), 
                new PrologOperator(1050,xfx,"from"),
                new PrologOperator(1050,xfy,"->"),
                new PrologOperator(1000,xfy,","),
                new PrologOperator(900,fy,"not"),
                new PrologOperator(900,fy,"\\+"),
                new PrologOperator(900,fy,"spy"),
                new PrologOperator(900,fy,"nospy"),
                new PrologOperator(700,xfx,"="),
                new PrologOperator(700,xfx,"\\="),
                new PrologOperator(700,xfx,"=="),
                new PrologOperator(700,xfx,"\\=="),
                new PrologOperator(700,xfx,"@<"),
                new PrologOperator(700,xfx,"@=<"),
                new PrologOperator(700,xfx,"@>"),
                new PrologOperator(700,xfx,"@>="),
                new PrologOperator(700,xfx,"=.."),
                new PrologOperator(700,xfx,"^=.."),
                new PrologOperator(700,xfx,"is"),
                new PrologOperator(700,xfx,"=:="),
                new PrologOperator(700,xfx,"=\\="),
                new PrologOperator(700,xfx,"<"),
                new PrologOperator(700,xfx,"=<"),
                new PrologOperator(700,xfx,">"),
                new PrologOperator(700,xfx,">="),
                new PrologOperator(661,xfy,"."),
                new PrologOperator(600,xfy,":"),
                new PrologOperator(500,yfx,"+"),
                new PrologOperator(500,yfx,"-"),
                new PrologOperator(500,yfx,"/\\"),
                new PrologOperator(500,yfx,"\\/"),
                new PrologOperator(500,fx,"+"),
                new PrologOperator(500,fx,"-"),
                new PrologOperator(400,yfx,"*"),
                new PrologOperator(400,yfx,"/"),
                new PrologOperator(400,yfx,"//"),
                new PrologOperator(400,yfx,"mod"),
                new PrologOperator(400,yfx,"<<"),
                new PrologOperator(400,yfx,">>"),
                new PrologOperator(400,yfx,"\\"),
                new PrologOperator(200,xfy,"^")
                };
        
        static class PrologOperator{
                int precedence;
                int type;
                String name;
                PrologOperator(int p,int t,String n){
                        if (t<xfx||t>yf||p<1||p>1200||n==null)
                                throw new IPException("Bad arguments in PrologOperator constructor");
                        precedence=p; type=t; name=n;
                }
        }
}

---