• 0xEAB (8/39) Dec 30 2018 Hey :)
• =?UTF-8?Q?Ali_=c3=87ehreli?= (9/18) Dec 30 2018 Function templates cannot be virtual functions. One reason is the
• 0xEAB (3/22) Jan 02 2019 Thanks for the technical explanation.

0xEAB <desisma heidel.beer> writes:

 void main()
 {
     StaticThingy.register(new SomeAdapter());
     StaticThingy.createSome!Dummy();
 }


 interface FooAdapter
 {
     FooBundle!(Handle) createSome(Handle)();
 }

 private class SomeAdapter : FooAdapter
 {
     Bundle createSome()
     {
         auto w = new Dummy();
         auto c = new FooDummy();
         auto b = Bundle(c, w);
         return b;
     }
 }

 struct StaticThingy
 {
 static:
     FooBundle!(Handle) createSome(Handle)()
     {
         return fooAdapter.createSome!(Handle)();
     }

 // ...


 error: undefined reference to 
 '_D9onlineapp10FooAdapter__T10createSomeTCQBn5DummyZQyMFZSQCd__T9FooBundleTQBiZQp'
 collect2: error: ld returned 1 exit status
 Error: linker exited with status 1


Hey :)

During playing around I came up with code similar to the example 
above.

As the title says, this code doesn't link.
For the full example please see: https://run.dlang.io/is/mr0u2i

- But should this even compile successfully?
- Does `SomeAdapter` even implement `FooAdapter` correctly?


  ~ Elias

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 12/30/2018 05:05 AM, 0xEAB wrote:

 interface FooAdapter
 {
     FooBundle!(Handle) createSome(Handle)();
 }


Function templates cannot be virtual functions. One reason is the 
compiler cannot know how large the virtual function table should be, and 
the other one is it's just a template, not the real thing (i.e. not a 
function).

 private class SomeAdapter : FooAdapter
 {
     Bundle createSome()


SomeAdapter.createSome is a function unrelated to FooAdapter.createSome. 
Their only relationship is through "name hiding."

 - Does `SomeAdapter` even implement `FooAdapter` correctly?

Yes because FooAdapter has no virtual function. :p

   ~ Elias

Ali

0xEAB <desisma heidel.beer> writes:

On Sunday, 30 December 2018 at 18:55:10 UTC, Ali Çehreli wrote:
 On 12/30/2018 05:05 AM, 0xEAB wrote:

 interface FooAdapter
 {
     FooBundle!(Handle) createSome(Handle)();
 }


 Function templates cannot be virtual functions. One reason is 
 the compiler cannot know how large the virtual function table 
 should be, and the other one is it's just a template, not the 
 real thing (i.e. not a function).

 private class SomeAdapter : FooAdapter
 {
     Bundle createSome()


 SomeAdapter.createSome is a function unrelated to 
 FooAdapter.createSome. Their only relationship is through "name 
 hiding."

 - Does `SomeAdapter` even implement `FooAdapter` correctly?

 Yes because FooAdapter has no virtual function. :p

   ~ Elias

 Ali

Thanks for the technical explanation.
   ~ Elias