Attached is a simple example that demonstrates my problem (with dmd 1.018).  It seems like inheriting from a class that contains functions that would satisfy an interface does not work.  Usually, I work around this by just adding a manual call to super's copy.  Unfortunately, this only works if super's member function is not final.  Any tips on how to work around this?

If line 7 is commented out:
test.d(6): class test.foo interface function bar.start is not implemented

If line 7 is present:
test.d(7): function test.foo.start cannot override final function tango.core.Thread.Thread.start

Jason House wrote:
> Attached is a simple example that demonstrates my problem (with dmd 1.018).  It seems like inheriting from a class that contains functions that would satisfy an interface does not work.  Usually, I work around this by just adding a manual call to super's copy.  Unfortunately, this only works if super's member function is not final.  Any tips on how to work around this?
> 
> If line 7 is commented out:
> test.d(6): class test.foo interface function bar.start is not implemented
> 
> If line 7 is present:
> test.d(7): function test.foo.start cannot override final function tango.core.Thread.Thread.start

The standard technique is to use an alias, like so:

interface Foo {
  int bar();
}

class A {
  int bar();
}

class B : A, Foo {
  alias A.bar bar;
}

Although, personally, I'm not entirely satisfied with this.  I would think checking for interface implementation warrants a look up the inheritance chain.  I think there was a reason given in an older discussion, but darned if I can remember it now.

-- Chris Nicholson-Sauls

Reply to Jason,

> Attached is a simple example that demonstrates my problem (with dmd
> 1.018).  It seems like inheriting from a class that contains functions
> that would satisfy an interface does not work.  Usually, I work around
> this by just adding a manual call to super's copy.  Unfortunately,
> this only works if super's member function is not final.  Any tips on
> how to work around this?
> 
> If line 7 is commented out:
> test.d(6): class test.foo interface function bar.start is not
> implemented
> If line 7 is present:
> test.d(7): function test.foo.start cannot override final function
> tango.core.Thread.Thread.start

alias the functions (I think you can even change the name to make it match)


interface I {int foo();}

class C { int bar(){...} }

class D : C, I {alias bar foo;}

Chris Nicholson-Sauls wrote:
> Jason House wrote:
>> Attached is a simple example that demonstrates my problem (with dmd 1.018).  It seems like inheriting from a class that contains functions that would satisfy an interface does not work.  Usually, I work around this by just adding a manual call to super's copy.  Unfortunately, this only works if super's member function is not final.  Any tips on how to work around this?
>>
>> If line 7 is commented out:
>> test.d(6): class test.foo interface function bar.start is not implemented
>>
>> If line 7 is present:
>> test.d(7): function test.foo.start cannot override final function tango.core.Thread.Thread.start
> 
> The standard technique is to use an alias, like so:
> 
> interface Foo {
>   int bar();
> }
> 
> class A {
>   int bar();
> }
> 
> class B : A, Foo {
>   alias A.bar bar;
> }
> 
> Although, personally, I'm not entirely satisfied with this.  I would think checking for interface implementation warrants a look up the inheritance chain.  I think there was a reason given in an older discussion, but darned if I can remember it now.
> 
> -- Chris Nicholson-Sauls


For whatever reason, that trick didn't work for me.  I got the same error as if I hadn't had the alias in there at all.

Reply to Jason,

> For whatever reason, that trick didn't work for me.  I got the same
> error as if I hadn't had the alias in there at all.
> 


could you post code?

what version are you using?