presto-main/src/main/java/io/prestosql/operator/scalar/JsonFunctions.java/JsonFunctions/varcharJsonArrayLength
class JsonFunctions:    @SqlNullable
    @ScalarFunction("json_array_length")
    @LiteralParameters("x")
    @SqlType(StandardTypes.BIGINT)
    public static Long varcharJsonArrayLength(@SqlType("varchar(x)") Slice json)
    {
        return jsonArrayLength(json);
    }