[fpc-devel] mantis 0038496 custom variants and documentation

[Marco van de Voort]

Op 2021-05-30 om 13:02 schreef Sven Barth via fpc-devel:
>
>>
>> I think it is allowed to change the result type of the variant passed 
>> in binaryop(), but am not 100% sure, and also not sure if there are 
>> other things to keep an eye for (e.g. finalization of the existing 
>> value).
>>
>> Does anybody know open source custom variant examples other than 
>> fmtbcd ?
>
> The only one I'm aware of that makes use of BinaryOp is Python4Delphi 
> ( 
> https://github.com/pyscripter/python4delphi/blob/master/Source/VarPyth.pas 
> ). mORMot derives its TSynInvokeableVariantType and thus its 
> TDocVariant from TInvokableVariantType, but does not override the 
> operator methods.
>
I think I saw this one before in March. I also remember the conclusion: 
this should be fixed in LefPromotion(), but FPC doesn't implement 
calling that method :-)