[fpc-devel] "Default" discussion for SmartPointers etc
Michael Van Canneyt
michael at freepascal.org
Thu Jul 28 08:21:28 CEST 2016
On Wed, 27 Jul 2016, Jonas Maebe wrote:
> On 27/07/16 22:47, Sven Barth wrote:
>> Am 27.07.2016 21:04 schrieb "Maciej Izak" <hnb.code at gmail.com
>> <mailto:hnb.code at gmail.com>>:
>>> In that case SmartPtr/SmartObj/Nullable type has no sense for me. The
>> basic purpose is excluded. You can do that today by using for example
> What is the basic purpose? I did not see any explanation of that in the
> original mail. It only said that it is vital to the smart pointers/ARC
> objects and nullable types implementation.
As far as I understand I think Izak wants (needs) 2 things:
- "Default" property for a property of records.
I think that this feature by itself presents little difficulty.
This is enough to implement "nillable" types, except for 1 thing.
- The ability to pass properties as var arguments.
I think this feature is not doable. The closest you can come to this is:
But this presents obvious timing problems: A.Prop is written only on return of the function.
Failing that, Izak tries to simulate the 'address' of the default property
of a record.
IMHO The first can be done, the solution to the second is a bad idea.
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