presto-main/src/main/java/io/prestosql/sql/gen/ExpressionCompiler.java/ExpressionCompiler/compilePageProcessor
class ExpressionCompiler:    public Supplier<PageProcessor> compilePageProcessor(Optional<RowExpression> filter, List<? extends RowExpression> projections)
    {
        return compilePageProcessor(filter, projections, Optional.empty());
    }