public Grouper( ResultSet output, GroupSpec[] group, AggSpec[] agg )
{
Output = output;
Group = group;
Agg = agg;
Rows = new G.HashSet<Value[]>( this );
}
public override void CheckNames( Exec e )
{
var set = new G.HashSet<string>();
for ( int i = 0; i < ColumnCount; i += 1 )
{
string name = Exps[ i ].Name;
if ( name == "" ) e.Error( "Unnamed expression" );
else if ( set.Contains(name) ) e.Error( "Duplicate name: " + name );
set.Add( name );
}
}