public static State MakeChoice( State block, State primitive )
{
if(primitive is Choice) {
Debug.Fail("primitive can't be a choice");
throw new InvalidOperationException();
}
if( block==emptySet )
return primitive;
if( primitive==emptySet )
return block;
if( block.Contains(primitive) )
return block;
return new Choice(block,primitive);
}
public override State Expand( AttributesSet attributes, State result )
{
if( result.Contains(this) ) return result; // no need to expand more
if( IsPersistent )
result = MakeChoice( result, this );
for( Transition.Att aa = aTr; aa!=null; aa=aa.Next ) {
int matchCount=0,failCount=0;
for( int j=attributes.Count-1; j>=0; j-- ) {
int nameCode = attributes.GetName(j);
if( aa.Accepts(nameCode) ) {
string value = attributes.GetValue(j);
State s = aa.Left;
s = s.Text( value, attributes.Context, AttributesSet.empty, emptySet );
if( s.IsFinal ) matchCount++;
else failCount++;
}
}
if( (matchCount==1 && failCount==0 && !aa.Repeated)
|| (matchCount!=0 && failCount==0 && aa.Repeated) )
result = aa.Right.Expand( attributes, result );
}
for( Transition.NoAtt nea = nTr; nea!=null; nea=nea.Next ) {
int j;
for( j=attributes.Count-1; j>=0; j-- ) {
int nc = attributes.GetName(j);
if( nea.Accepts(nc) )
// this attribute is prohibited.
break;
}
if(j==-1)
result = nea.Right.Expand( attributes, result );
}
for( Transition.Interleave ia = iTr; ia!=null; ia=ia.Next ) {
result = MakeChoice( result, MakeInterleave(
ia.Left. Expand( attributes, emptySet ),
ia.Right.Expand( attributes, emptySet ),
ia ));
}
return result;
}