presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitCurrentRowBound
class AstBuilder:    @Override
    public Node visitCurrentRowBound(SqlBaseParser.CurrentRowBoundContext context)
    {
        return new FrameBound(getLocation(context), FrameBound.Type.CURRENT_ROW);
    }