[fpc-pascal] Tuples as variant arrays

[Michael Van Canneyt]

On Fri, 25 Jun 2021, Dennis Lee Bieber via fpc-pascal wrote:

> On Fri, 25 Jun 2021 16:12:41 -0600, Ryan Joseph via fpc-pascal
> <fpc-pascal at lists.freepascal.org> declaimed
> the following:
>
>> Is it possible something like this could work? Seems like it should but I get an error (got MyRecord expected variant).
>>
>> ====================================
>>
>> {$mode objfpc}
>>
>> program unit_name;
>>
>> type
>>  TTuple = array of variant;
>>
>> type
>>  MyRecord = record
>>  end;
>>
> 	Uhm, is there supposed to be some name designating storage space inside
> that record declaration? Just my initial observation -- my Pascal
> experience is Jensen&Wirth via UCSD (college, on LSI-11) and Alcor (on
> TRS-80 Model 4).
>
>> var
>>  t: TTuple;
>>  r: MyRecord;
>>  i: variant;
>> begin
>>  t := [1,'string', r];
>
> https://wiki.freepascal.org/Variant
> """
> Values of any simple data type can be stored in a variant variable.
> """
> ... would seem to reject the use of a record type (as records are,
> themselves, made up of other "simple data types").

It is not possible to do this unless you create some custom variant manager
that can handle this. But even so, you'd need to make it a pointer to a
record, as a variant has limited, fixed size.

Michael.