• =?UTF-8?Q?Christian_K=c3=b6stlin?= (14/14) Mar 02 2018 To give an example:
• Steven Schveighoffer (8/24) Mar 02 2018 Yes:
• =?UTF-8?Q?Christian_K=c3=b6stlin?= (16/45) Mar 02 2018 Thanks for this.
• =?UTF-8?Q?Christian_K=c3=b6stlin?= (1/14) Mar 02 2018 This seems to be connected to Thread.start being a final function.
• H. S. Teoh (7/21) Mar 02 2018 Well, yes, you cannot override a final function. That is the point of
• Jacob Carlborg (10/22) Mar 06 2018 You can also try a template this parameter [1] in the base class:

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

To give an example:

class Thread {
  ...
  Thread start() {...}
}

class Timer : Thread {
  ...
}


void main() {
  // Timer timer = new Timer().start;  // this does not work
  auto timer = new Timer().start; // because timer is of type Thread
}


thanks in advance,
christian

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 3/2/18 3:23 PM, Christian Köstlin wrote:
 To give an example:
 
 class Thread {
    ...
    Thread start() {...}
 }
 
 class Timer : Thread {
    ...
 }
 
 
 void main() {
    // Timer timer = new Timer().start;  // this does not work
    auto timer = new Timer().start; // because timer is of type Thread
 }

Yes:

class Timer : Thread {
    override Timer start() { ... }
}

https://dlang.org/spec/function.html#virtual-functions

(see item 6)

-Steve

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

On 02.03.18 21:39, Steven Schveighoffer wrote:
 On 3/2/18 3:23 PM, Christian Köstlin wrote:
 To give an example:

 class Thread {
    ...
    Thread start() {...}
 }

 class Timer : Thread {
    ...
 }


 void main() {
    // Timer timer = new Timer().start;  // this does not work
    auto timer = new Timer().start; // because timer is of type Thread
 }

 
 Yes:
 
 class Timer : Thread {
    override Timer start() { ... }
 }
 
 https://dlang.org/spec/function.html#virtual-functions
 
 (see item 6)
 
 -Steve

Thanks for this.
It works for me only without the override (with override I get
Error: function timer.Timer.start does not override any function, did
you mean to override 'core.thread.Thread.start'?).

Although I wonder if its possible to "fix" this in the Thread class with
some dlang magic. e.g. traits
class Thread {
  traits(GetClass) start() {...}
}

or perhaps

class ThreadHelper(T) : Thread {
  override T start() {return cast(T)super.start();}
}
class Timer : Thread!Timer {
}

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

 class Timer : Thread {
    override Timer start() { ... }
 }

 https://dlang.org/spec/function.html#virtual-functions

 (see item 6)

 -Steve

 Thanks for this.
 It works for me only without the override (with override I get
 Error: function timer.Timer.start does not override any function, did
 you mean to override 'core.thread.Thread.start'?).

This seems to be connected to Thread.start being a final function.

"H. S. Teoh" <hsteoh quickfur.ath.cx> writes:

On Sat, Mar 03, 2018 at 01:13:43AM +0100, Christian Köstlin via
Digitalmars-d-learn wrote:
 class Timer : Thread {
    override Timer start() { ... }
 }

 https://dlang.org/spec/function.html#virtual-functions

 (see item 6)

 -Steve

 Thanks for this.
 It works for me only without the override (with override I get
 Error: function timer.Timer.start does not override any function,
 did you mean to override 'core.thread.Thread.start'?).

 This seems to be connected to Thread.start being a final function.

Well, yes, you cannot override a final function.  That is the point of
`final`. :-D

If you meant to override it after all, remove the `final`.


T

-- 
Life is complex. It consists of real and imaginary parts. -- YHL

Jacob Carlborg <doob me.com> writes:

On 2018-03-02 21:23, Christian Köstlin wrote:
 To give an example:

 class Thread {
    ...
    Thread start() {...}
 }

 class Timer : Thread {
    ...
 }


 void main() {
    // Timer timer = new Timer().start;  // this does not work
    auto timer = new Timer().start; // because timer is of type Thread
 }

You can also try a template this parameter [1] in the base class:

class Thread
{
     T start(this T) () { ... }
}

But if this "Thread" is core.thread.Thread that won't work.

[1] https://dlang.org/spec/template.html#template_this_parameter

-- 
/Jacob Carlborg