/*     ____ ____  ____ ____  ______                                     *\
**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
** /_____/\____/\___/\____/____/                                        **
**                                                                      **
** $Id$
\*                                                                      */

package scalac.transformer.matching;

import ch.epfl.lamp.util.Position;
import scalac.*;
import scalac.ast.*;
import scalac.symtab.*;
import scalac.typechecker.*;

/** intermediary data structure for algebraic matching
 */

public class PatternNode {
    public int pos = Position.FIRSTPOS;
    public Type type;
    public PatternNode or;
    public PatternNode and;

    public case Header( Tree selector, Header next );
    public case Body( Tree.ValDef[][] bound, Tree[] guard, Tree[] body );
    public case DefaultPat();
    public case ConstrPat( Symbol casted );
    public case SequencePat( Symbol casted, int len ); // only used in PatternMatcher
    public case SeqContainerPat( Symbol casted, Tree seqpat ); //   in AlgebraicMatcher
    public case ConstantPat( Object value );
    public case VariablePat( Tree tree );


    public Symbol symbol() {
        switch (this) {
            case ConstrPat( Symbol casted ):
                return casted;
            case SequencePat( Symbol casted, _ ):
                return casted;
            case SeqContainerPat( Symbol casted, _ ):
                return casted;
            default:
                return Symbol.NONE;
        }
    }

    public String toString() {
        switch (this) {
            case Header( Tree selector, Header next ):
                return "Header(" + selector + ")";
            case Body( _, _, _ ):
                return "Body";
            case DefaultPat():
                return "DefaultPat";
            case ConstrPat( Symbol casted ):
                return "ConstrPat(" + casted + ")";
            case SequencePat( Symbol casted, int len ):
                return "SequencePat(" + casted + ", " + len + "...)";
            case SeqContainerPat( Symbol casted, Tree seqpat ):
                return "SeqContainerPat(" + casted + ", " + seqpat + ")";
            case ConstantPat( Object value ):
                return "ConstantPat(" + value + ")";
            case VariablePat( Tree tree ):
                return "VariablePat";
            default:
                return "<unknown pat>";
        }
    }
}