[fpc-pascal] why can't we define class operator for old fashion object type, but ok for 'advanced record' type?

[Michael Van Canneyt]

> Am 15.08.2018 um 17:29 schrieb Michael Van Canneyt:
>>
>>
>> On Wed, 15 Aug 2018, Sven Barth via fpc-pascal wrote:
>>
>>>>
>>>> But maybe you are using mode delphi ? If so, try separating out the
>>>> object
>>>> definition in a separate unit which is not compiled in delphi mode.
>>> A global operator won't help at all as (currently) the operator won't
>>> be visible during the specialization. Only if the operator is visible
>>> during the *generic's* declaration it would be picked up.
>>
>> That is contrary to the class operator, which is also only visible
>> during
>> specialization, after all.
>>
>> Is there a reason for this behaviour ?
> The operator of a record is visible together with the record, however a
> global operator is not. When specializing the unit scope of the
> declaration of the *generic* is restored thus no helpers or global
> operators of the current scope are visible except they are part of the
> type parameter.
> I do want to try to change this in the future, but I need to be careful
> to not open a different can of worms (as Delphi doesn't do it this way).

Purely reasoning in terms of data structures:

I would think you 'attach' operators to the type for which they are defined ?
If the 'attach' link structure contains the unit in which the operator
definition resides, you can check whether this unit is visible, and if
yes, the operator is 'usable'.

Michael.