Emulate C's (polymorphic) NULL type

ParticlePeter via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Mon Jun 6 05:09:33 PDT 2016


On Monday, 6 June 2016 at 11:40:11 UTC, Anonymouse wrote:
> On Monday, 6 June 2016 at 09:43:23 UTC, ParticlePeter wrote:
>> In C NULL can be used as integer as well as null pointer.
>> Is there a way to create such a type in D?
>>
>> The type should have only one value which is obviously 
>> (0/null).
>> A extern( C ) function should be able to take it as either one.
>>
>> Overloaded enum pops into my mind as example:
>> enum NULL = 0;
>> enum NULL = null;
>>
>>
>> Is this possible somehow?
>
> If you want it for use in logical expressions then implicit 
> boolean conversion will treat them as the same.
>
> https://dpaste.dzfl.pl/d82f60657c37

I don't see the connection here, you introduced two symbols with 
two different types. I want one symbol which can pose as two 
different (constant) types.


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