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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
import java.io._;
import java.util._;
import scalac.{Global => scalac_Global};
import scalac._;
import scalac.ast._;
import scalac.symtab._;
import scalac.util._; // Names
import Tree._;
import scalac.transformer.{ OwnerTransformer => scalac_transformer_OwnerTransformer };
import scalac.transformer.matching.PartialMatcher ;
import scalac.transformer.matching.PatternMatcher ;
import scalac.transformer.matching.TestRegTraverser ;
import scalac.transformer.matching.AlgebraicMatcher ;
/** A transformer for expanding match expressions into
* flat sequences of .is and .as method calls
*
* @author Matthias Zenger, Burak Emir
* @version 1.1
*/
package scala.tools.scalac.transformer {
import matching.FullRegularTranslator ;
import matching.GrammarPrinter ; //DEBUG
class TransMatch( global:scalac_Global )
extends scalac_transformer_OwnerTransformer( global ) {
var cunit:Unit = null;
override def apply( cunit:Unit ):unit = {
this.cunit = cunit;
super.apply( cunit );
}
import Tree._ ;
/*
def singleSeq(t:Array[Tree]) = {
t.length == 1 && t(0).isInstaceOf[Sequence] && val ts = Iterator.fromArray( t );
(( trees.length == 1 ) &&
( trees( 0 ) match {
case Sequence( trees2 ) =>
(( trees2.length == 1 ) &&
( trees2( 0 ) match {
case Sequence( trees3 )=>
true;
case _ => isRegular( trees2 );
}
})) || ( trees2.length != 0 ) && isRegular( trees2 )
case _ => false
})) ||
}
*/
def isRegular(ps:Array[Tree]):Boolean = {
var res = false;
val pats = scala.Iterator.fromArray( ps );
while (!res && pats.hasNext )
res = isRegular( pats.next );
res
}
def isRegular(pat:Tree):Boolean = pat match {
case Alternative(_) => true;
case Bind( n, pat1 ) =>
TreeInfo.isNameOfStarPattern( n ) || TreeInfo.isEmptySequence( pat1 )
case Tree$Ident(n) => TreeInfo.isNameOfStarPattern( n )
case Sequence( trees ) =>
true;//( trees.length != 0 )||isRegular( trees );
case Apply( fn, trees ) =>
isRegular( trees ) &&
!((trees.length == 1) && TreeInfo.isEmptySequence( trees( 0 )))
case _ => false;
}
def transform( root:Tree, cases:Array[Tree$CaseDef], restpe:Type ):Tree = {
if( global.newMatch ) {
val fm = new FullRegularTranslator( global );
val gram = fm.MakeGrammar( scala.Iterator.fromArray( cases ) );
Console.println( GrammarPrinter.toString( gram ));
throw new ApplicationError("not impl.");
};
var containsReg = false;
var i = 0;
while (i < cases.length) {
containsReg = TestRegTraverser.apply(cases( i )) || containsReg;
//containsReg = isRegular(cases(i).pat) || containsReg;
//TestRegTraverser.apply(cases( i ));
var nilvars:Set = TestRegTraverser.getNilVariables();
if( !nilvars.isEmpty() ) {
val newBody = new Array[Tree]( nilvars.size() );
var j=0;
var it:Iterator = nilvars.iterator();
while( it.hasNext() ) {
val v:Symbol = it.next().asInstanceOf[ Symbol ];
val n = gen.mkNil(cases(i).pos);
newBody( j ) = gen.ValDef(v, n);
j = j + 1;
}
cases(i).body = gen.mkBlock( newBody, cases(i).body );
}
i = i+1;
}
if( containsReg ) {
val am = new AlgebraicMatcher( cunit );
val matcher = new PartialMatcher( currentOwner, root, restpe );
am.construct( matcher, cases.asInstanceOf[ Array[Tree] ] );
matcher.tree
} else {
val pm = new PatternMatcher( cunit, root, currentOwner, restpe );
try{
pm.construct( cases.asInstanceOf[ Array[Tree] ] );
} catch {
case e:Throwable =>
Console.println("failed on pats"+scala.Iterator.fromArray(cases).toList.mkString("","\n","")+", message\n"+e.getMessage())
}
if (global.log()) {
global.log("internal pattern matching structure");
pm.print();
}
pm.toTree();
}
}
/** evil hack. OwnerTransformer should have this function */
def transform1(ts:Array[Tree$CaseDef]):Array[Tree$CaseDef] = {
var i = 0;
while( i < ts.length ) {
val t = transform(ts( i ));
if (t != ts( i )) {
val res = new Array[Tree$CaseDef](ts.length);
System.arraycopy(ts, 0, res, 0, i);
res( i ) = t.asInstanceOf[Tree$CaseDef];
i = i + 1;
while(i < ts.length) {
res( i ) = transform(ts( i )).asInstanceOf[Tree$CaseDef];
i = i + 1
};
return res;
};
i = i + 1;
}
return ts;
}
override def transform( tree:Tree ):Tree = {
if (tree == null)
return null;
else
tree match {
case Tree$Apply(Tree$Select( receiver, Names.match ), args) =>
if ((args != null) && (args.length == 1))
args( 0 ) match {
case Tree$Visitor( cases ) =>
return transform(transform(receiver), transform1(cases), tree.getType());
}
return tree;
case Tree$Apply(Tree$TypeApply(Tree$Select( receiver, Names.match ), targs), args) =>
if ((args != null) && (args.length == 1))
args( 0 ) match {
case Tree$Visitor( cases ) =>
return transform(transform(receiver), transform1(cases), tree.getType());
}
return tree;
case _ =>
super.transform(tree);
}
}
}
}
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