path: root/sources/scalac/transformer/matching/WordAutomInScala.java

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

// $Id$

package scalac.transformer.matching;

import ch.epfl.lamp.util.Position;

import scalac.*;
import scalac.ast.Tree;
import scalac.ast.TreeGen;
import scalac.symtab.Type;
import scalac.symtab.Symbol;
import scalac.transformer.TransMatch.Matcher;
import scalac.typechecker.*;
import Tree.*;

import java.util.*;


/**
 */
public class WordAutomInScala extends Autom2Scala {

    Tree getMatcherSwitch(Tree selector,
                          Tree failTree,
                          Tree body[],
                          Type resultType) {

        Tree run = callFun( new Tree[] {
                       cf.newIterator(selector),
                       gen.mkIntLit(Position.FIRSTPOS, 0) } );

        /* return code `var <swres>: scala.Int = <init>' */

        run = _intvar(resultSym, run);

        Tree result;

        // conditions
        Tree cond[] = new Tree[body.length];
        //Tree bbody[] = new Tree[body.length];
        for (int i = body.length - 1; i >= 0; i--)
            cond[i] = cf.Equals(_swres(), gen.mkIntLit(Position.FIRSTPOS, i));

        result = cf.Switch( selector, cond, body, failTree );

        result = cf.gen.mkBlock( pos, new Tree[] { theDefDef, run, result } );
        //unit.global.debugPrinter.print( result );
        return result;
    }

    /** do the translation
     */
    public void translate() {
        initializeSyms();
        Tree tb = code_body_NEW();
        theDefDef = gen.DefDef(this.funSym, tb);
    }

    /** ...
     * @return returns translation of transition with label from i.
     * returns null if there is no such transition
     * (no translation needed)
     */
    Tree code_delta(int i, Label label) {
        Integer target = dfa.delta(i, label);

        if (target == null)
            switch (label) {
            case DefaultLabel:
                return code_fail(); // this may not happen !
            default:
                return null; // not good
            }
        else if (target.intValue() == dfa.nstates - 1) // that one is a dead state
            return code_fail();

        return callFun(new Tree[] { _iter(),
            gen.mkIntLit(Position.FIRSTPOS, target.intValue())} );
    }

    /** ...
     * @param dfa ...
     * @param elementType ...
     * @param owner ...
     * @param cf ...
     * @return ...
     */
    public WordAutomInScala(DetWordAutom dfa,
                            Type elementType,
                            Symbol owner,
                            CodeFactory cf,
			    boolean optim) {
        super(dfa, elementType, owner, cf);

        this.optimize &= optim;

    }

}