presto-main/src/main/java/io/prestosql/operator/scalar/StringFunctions.java/StringFunctions/length
class StringFunctions:    @Description("count of code points of the given string")
    @ScalarFunction
    @LiteralParameters("x")
    @SqlType(StandardTypes.BIGINT)
    public static long length(@SqlType("varchar(x)") Slice slice)
    {
        return countCodePoints(slice);
    }