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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 scalac.transformer.{ OwnerTransformer => scalac_transformer_OwnerTransformer };
//import scalac.transformer.matching.PatternMatcher ;
//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.PatternMatcher ;
import matching.PartialMatcher ;
//import matching.FullRegularTranslator ;
class TransMatch( global:scalac_Global )
extends scalac_transformer_OwnerTransformer( global ) {
import Tree._ ;
var cunit:CompilationUnit = null;
override def apply( cunit:CompilationUnit ):unit = {
this.cunit = cunit;
super.apply( cunit );
}
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 )
|| isRegular( pat1 )
case Ident(n) => false
case Sequence( trees ) =>
( trees.length == 0 ) || isRegular( trees );
case Apply( fn, trees ) =>
isRegular( trees ) &&
!((trees.length == 1) && TreeInfo.isEmptySequence( trees( 0 )))
case Literal(_) => false;
case Select(_,_) => false;
case Typed(_,_) => false;
case _ => error("in TransMatch.isRegular phase: unknown node"+pat.getClass());
}
def nilVariables( pat:Tree ) = {
var res:scala.List[Symbol] = Nil;
def getNilVars1( ps:Array[Tree] ):scala.Unit = {
val z:Seq[Tree] = ps; z.elements.foreach( x => getNilVars( x ));
}
def getNilVars( p:Tree ):scala.Unit = p match {
case Alternative( _ ) => /* no bind allowed! */
case Bind( _, pat ) =>
getNilVars(pat);
if( TreeInfo.isEmptySequence( pat ) )
res = p.symbol() :: res;
case Ident(_) =>
case Sequence( trees ) => getNilVars1( trees )
case Apply( _, args ) => getNilVars1( args )
case Literal(_) =>
case Select(_,_) =>
case Typed(_,_) =>
case _ => error("in TransMatch.nilVariables: unknown node"+pat.getClass());
}
getNilVars( pat );
res
}
// 2do: remove binds from pattern
def handleNilVariables( cse: CaseDef ): Unit = {
val nilvars = nilVariables(cse.pat);
if( !nilvars.isEmpty ) {
val newBody = new Array[Tree]( nilvars.length );
var j=0;
for( val v <- nilvars.elements ) {
val n = gen.mkNil( cse.pos );
newBody( j ) = gen.ValDef( v, n );
j = j + 1;
}
cse.body = gen.mkBlock( newBody, cse.body );
}
}
//val bsf = new scala.util.automaton.BerrySethi[ matching.PatternTest ]( pe );
def transform( root:Tree, cases:Array[CaseDef], restpe:Type ):Tree = {
if( global.newMatch ) {
//val fm = new FullRegularTranslator( global );
//val gram = fm.MakeGrammar( scala.Iterator.fromArray( cases ) );
//Console.println("writing out the grammar to /tmp/encodedGrammar.bin");
////val f = new FileOutputStream(new File("/tmp/encodedGrammar.bin"));
////f.write( gram.encode );
////f.close();
//// val gram = Predef.decode( Predef.Array[] );
//Console.println( gram.encode);
throw new ApplicationError("not impl.");
};
var containsReg = false;
var i = 0;
while (i < cases.length) {
if(isRegular(cases( i ).pat)) {
containsReg = true;
handleNilVariables(cases( i ));
}
i = i+1;
}
if( containsReg ) {
/*
val pe = new matching.PatternExp(global.definitions); // TEST
var j = 0;
val pat = new Array[pe.RegExp](cases.length);
while( j < cases.length) {
pat(j) = pe.fromTree(cases(j).pat);
j = j + 1;
} // TEST
*/
val am = new matching.AlgebraicMatcher( cunit );
val matcher = new PartialMatcher( currentOwner, root, restpe );
am.construct( matcher, cases.asInstanceOf[ Array[Tree] ] );
matcher.tree
} else {
val pm = new matching.PatternMatcher( cunit );
pm.initialize(root, currentOwner, restpe, true );
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[CaseDef]):Array[CaseDef] = {
var i = 0;
while( i < ts.length ) {
val t = transform(ts( i ));
if (t != ts( i )) {
val res = new Array[CaseDef](ts.length);
System.arraycopy(ts, 0, res, 0, i);
res( i ) = t.asInstanceOf[CaseDef];
i = i + 1;
while(i < ts.length) {
res( i ) = transform(ts( i )).asInstanceOf[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 Apply(Select( receiver, Names._match ), args) =>
if ((args != null) && (args.length == 1))
args( 0 ) match {
case Visitor( cases ) =>
return transform(transform(receiver), transform1(cases), tree.getType());
}
return tree;
case Apply(TypeApply(Select( receiver, Names._match ), targs), args) =>
if ((args != null) && (args.length == 1))
args( 0 ) match {
case Visitor( cases ) =>
return transform(transform(receiver), transform1(cases), tree.getType());
}
return tree;
case _ =>
super.transform(tree);
}
}
}
}
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