On 2019-09-29 11:31, Kirinn wrote:
I'd like to ask for some clarification on this issue:


Dwords can't be passed into an array of const, because TVarRec doesn't
have an unsigned 32-bit integer type. Adding any kind of handling for
it would be Delphi-incompatible. But isn't the point of the ObjPas
mode to be able to fix regrettable oversights that Delphi has? Can't a
special case be added for accepting Dwords in ObjPas mode only?

That is generally only possible if such a change is confined to the unit compiled in (Obj)FPC mode. Otherwise the interoperability between code written in different modes –which can be several layers deep, of which you as "top level" user may have no idea– becomes a matter of luck (or being extremely careful and having the source code of everything available, or at least information about the mode the code was written in).

that vtQWord and vtUnicodeString are already extensions going beyond
Delphi. Why not Dword?

FPC supported an unsigned 64 bit integer type before Delphi did, so at the time vtQWord was added, there was no Delphi behaviour to be compatible with. When Delphi later introduced an unsigned 64 bit integer type but no vtQWord, the choice was between breaking backward compatibility with existing FPC code or keeping an incompatibility with Delphi. In such no-win situations, we generally opt for keeping FPC compatibility.

And at least current versions of Delphi also support vtUnicodeString.

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