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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
** **
** $Id$
\* */
package scalac.transformer.matching;
import scalac.Global;
import scalac.ast.*;
import scalac.util.*;
import scalac.symtab.*;
import java.util.*;
public class TestRegTraverser extends Traverser {
boolean result = false;
Set variables = new HashSet();
static Set nilVariables = new HashSet();
public void traverse(Tree tree) {
if (!result)
switch (tree) {
case Alternative(_):
result = true;
break;
case Bind(_, Tree pat):
if( TreeInfo.isEmptySequence( pat ) ) {
// annoying special case: b@() [or b@(()|()) after normalization]
//System.err.println("bindin empty "+tree.symbol());
nilVariables.add(tree.symbol());
result = true;
} else {
variables.add(tree.symbol());
}
traverse(pat);
break;
case Ident(_):
Symbol symbol = tree.symbol();
if ((symbol != Global.instance.definitions.PATTERN_WILDCARD) &&
variables.contains(symbol))
result = true;
break;
case CaseDef(Tree pat, _, _):
traverse(pat);
break;
case Sequence( Tree[] trees):
//result = true;
traverse( trees );
//result = true;
break;
default:
super.traverse( tree );
}
}
public static boolean apply(Tree t) {
TestRegTraverser trt = new TestRegTraverser();
nilVariables.clear();
trt.traverse(t);
//System.err.println("TestRegTraverser says "+t+" -> "+trt.result);
return trt.result;
}
public static Set getNilVariables() {
return nilVariables;
}
}
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