digitalmars.D.learn - Placement of shared does not allow to set a delegate

Tolga Cakiroglu (26/26) Jun 16 2014 In a class I defined an event attribute as follows:

=?UTF-8?B?QWxpIMOHZWhyZWxp?= (28/50) Jun 16 2014 shared{}

Tolga Cakiroglu (8/34) Jun 16 2014 Thanks Ali. That has solved the problem. Actually I tried to use
Tolga Cakiroglu (27/53) Jun 16 2014 Okay, now I continue with another thing. After defining the event

=?UTF-8?B?QWxpIMOHZWhyZWxp?= (38/64) Jun 16 2014 The second type is different with dmd 2.066:

Tolga Cakiroglu (36/50) Jun 19 2014 Yes the understanding is correct. I simplified the code a little:

"Tolga Cakiroglu" <tcak pcak.com> writes:

In a class I defined an event attribute as follows:

public void delegate( shared(SocketListener) sender ) 
eventWhenStarted;

---

An instance of SocketListener is created.

auto listener = new shared SocketListener();

---

I defined a shared method that will be called when the event 
occurs.

public void listener_whenStarted( shared(SocketListener) sender ) 
shared{}

---

I set the event attribute of listener to defined method:

listener.eventWhenStarted = &listener_whenStarted;

----

Here is the error message:

main.d(21): Error: cannot implicitly convert expression 
(&this.listener_whenStarted) of type void 
delegate(shared(SocketListener) sender) shared to shared(void 
delegate(shared(SocketListener)))


If we look at types separately as follows:

.......void delegate(shared(SocketListener) sender) shared
shared(void delegate(shared(SocketListener)))


Isn't the first type same as the second one?


(1.5 years later, I still hate the `shared` keyword. It is 
nothing but confusion and extra coding for many programmers.)

Jun 16 2014

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 06/16/2014 05:35 AM, Tolga Cakiroglu wrote:> In a class I defined an 
event attribute as follows:
 public void delegate( shared(SocketListener) sender ) eventWhenStarted;

 ---

 An instance of SocketListener is created.

 auto listener = new shared SocketListener();

 ---

 I defined a shared method that will be called when the event occurs.

 public void listener_whenStarted( shared(SocketListener) sender ) 

shared{}
 ---

 I set the event attribute of listener to defined method:

 listener.eventWhenStarted = &listener_whenStarted;

 ----

 Here is the error message:

 main.d(21): Error: cannot implicitly convert expression
 (&this.listener_whenStarted) of type void
 delegate(shared(SocketListener) sender) shared to shared(void
 delegate(shared(SocketListener)))


 If we look at types separately as follows:

 .......void delegate(shared(SocketListener) sender) shared
 shared(void delegate(shared(SocketListener)))


 Isn't the first type same as the second one?


 (1.5 years later, I still hate the `shared` keyword. It is nothing but
 confusion and extra coding for many programmers.)

Here is a minimal example that reproduces the issue and the hint that 
compiles the code:

class SocketListener
{
     public void delegate( shared(SocketListener) sender )
     /* shared */    // <-- UNCOMMENT TO COMPILE
     eventWhenStarted;
}

class C
{
     this()
     {
         auto listener = new shared SocketListener();
         listener.eventWhenStarted = &listener_whenStarted;
     }

     public void listener_whenStarted( shared(SocketListener) sender ) 
shared
     {}
}

void main()
{}

Error: cannot implicitly convert expression (&this.listener_whenStarted) 
of type void delegate(shared(SocketListener) sender) shared to 
shared(void delegate(shared(SocketListener)))

Ali

Jun 16 2014

"Tolga Cakiroglu" <tcak pcak.com> writes:

Thanks Ali. That has solved the problem. Actually I tried to use 
that `shared` as follows before:

public shared void delegate( shared(BasicSocketListener) sender ) 
eventWhenStarted;

Though it didn't work with that. When it is put "before" the 
attribute name, it works now. It is just confusing where to put 
it to.

On Monday, 16 June 2014 at 15:25:51 UTC, Ali Çehreli wrote:
 Here is a minimal example that reproduces the issue and the 
 hint that compiles the code:

 class SocketListener
 {
     public void delegate( shared(SocketListener) sender )
     /* shared */    // <-- UNCOMMENT TO COMPILE
     eventWhenStarted;
 }

 class C
 {
     this()
     {
         auto listener = new shared SocketListener();
         listener.eventWhenStarted = &listener_whenStarted;
     }

     public void listener_whenStarted( shared(SocketListener) 
 sender ) shared
     {}
 }

 void main()
 {}

 Error: cannot implicitly convert expression 
 (&this.listener_whenStarted) of type void 
 delegate(shared(SocketListener) sender) shared to shared(void 
 delegate(shared(SocketListener)))

 Ali

Jun 16 2014

"Tolga Cakiroglu" <tcak pcak.com> writes:

On Monday, 16 June 2014 at 15:25:51 UTC, Ali Çehreli wrote:
 Here is a minimal example that reproduces the issue and the 
 hint that compiles the code:

 class SocketListener
 {
     public void delegate( shared(SocketListener) sender )
     /* shared */    // <-- UNCOMMENT TO COMPILE
     eventWhenStarted;
 }

 class C
 {
     this()
     {
         auto listener = new shared SocketListener();
         listener.eventWhenStarted = &listener_whenStarted;
     }

     public void listener_whenStarted( shared(SocketListener) 
 sender ) shared
     {}
 }

 void main()
 {}

 Error: cannot implicitly convert expression 
 (&this.listener_whenStarted) of type void 
 delegate(shared(SocketListener) sender) shared to shared(void 
 delegate(shared(SocketListener)))

 Ali


Okay, now I continue with another thing. After defining the event 
attribute as follows

public void delegate( shared(SocketListener) sender ) shared 
eventWhenStarted;


---


I removed the "shared" keyword from that method

public void listener_whenStarted( shared(SocketListener) sender 
){}


---


Then set the attribute as follows

listener.eventWhenStarted = cast(shared)(&listener_whenStarted);


---


There is error again.

main.d(21): Error: cannot implicitly convert expression 
(&this.listener_whenStarted) of type shared(void 
delegate(shared(SocketListener))) to shared(void 
delegate(shared(SocketListener)))

---

This error is important, because both types are completely same:

main.d(21): Error: cannot implicitly convert expression 
(&this.listener_whenStarted) of type

shared(void delegate(shared(SocketListener)))
to
shared(void delegate(shared(SocketListener)))

---

Can this be a bug?

Jun 16 2014

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 06/16/2014 09:37 AM, Tolga Cakiroglu wrote:

 On Monday, 16 June 2014 at 15:25:51 UTC, Ali Çehreli wrote:

 Okay, now I continue with another thing. After defining the event
 attribute as follows

 public void delegate( shared(SocketListener) sender ) shared
 eventWhenStarted;


 ---


 I removed the "shared" keyword from that method

 public void listener_whenStarted( shared(SocketListener) sender ){}


 ---


 Then set the attribute as follows

 listener.eventWhenStarted = cast(shared)(&listener_whenStarted);


 ---


 There is error again.

 main.d(21): Error: cannot implicitly convert expression
 (&this.listener_whenStarted) of type shared(void
 delegate(shared(SocketListener))) to shared(void
 delegate(shared(SocketListener)))

 ---

 This error is important, because both types are completely same:

 main.d(21): Error: cannot implicitly convert expression
 (&this.listener_whenStarted) of type

 shared(void delegate(shared(SocketListener)))
 to
 shared(void delegate(shared(SocketListener)))

The second type is different with dmd 2.066:

Error: cannot implicitly convert expression (&this.listener_whenStarted) 
of type

shared(void delegate(shared(SocketListener)))
to
shared(void delegate(shared(SocketListener)) shared)

However, I may have misunderstood your description. This is the code I 
tried:

class SocketListener
{
     public void delegate( shared(SocketListener) sender ) shared 
eventWhenStarted;
}

class C
{
     this()
     {
         auto listener = new shared SocketListener();
         listener.eventWhenStarted = cast(shared)&listener_whenStarted;
     }

     public void listener_whenStarted( shared(SocketListener) sender )
     {}
}

void main()
{}

 ---

 Can this be a bug?

I don't know but I theorize like this: :) There are three 'shared' 
qualifiers in the last error message.

shared(void delegate(shared(SocketListener)) shared)

1) The 'shared' in the middle: That one makes the delegate take a 
shared(SocketListener) argument when it gets called.

2) The 'shared' on the right-hand side: (I am not sure about this one.) 
That one makes the context pointer of the delegate 'shared'. For 
example, the delegate can only be called on a shared class object.

3) The 'shared' on the left-hand side: That one makes the type of the 
delegate shared so that e.g. such a delegate can be passed between threads.

That's what I understand.

Ali

Jun 16 2014

"Tolga Cakiroglu" <tcak pcak.com> writes:

Yes the understanding is correct. I simplified the code a little:
IMPORTANT: DMD 2.065 is used.

class Car{
	void delegate() onEvent;
}

class Test{
	this() shared
	{
		auto car = new shared Car();

		assert( typeid( car.onEvent ).toString() == "shared(void 
delegate())" );
		assert( typeid( &car_onEvent1 ).toString() == "void delegate()" 
);
		assert( typeid( &car_onEvent2 ).toString() == "void delegate()" 
);
		assert( typeid( cast(shared)( &car_onEvent2 ) ).toString() == 
"shared(void delegate())" );

		car.onEvent = &car_onEvent1;
		car.onEvent = &car_onEvent2; // COMPILATION ERROR
		car.onEvent = cast(shared)( &car_onEvent2 ); // COMPILATION 
ERROR
	}

	void car_onEvent1(){}
	void car_onEvent2() shared{}
}

void main(){
	new shared Test();
}

I just want to know if I am doing a mistake, thinking in wrong 
way, or there is a bug.

The first compilation error is that it cannot convert "void 
delegate() shared" to "shared(void delegate())".

The second compilation error is that it cannot convert 
"shared(void delegate())" to "shared(void delegate())".

(Since DMD 2.066 is not ready yet, I need to continue with 2.065.)


On Tuesday, 17 June 2014 at 04:35:10 UTC, Ali Çehreli wrote:
 I don't know but I theorize like this: :) There are three 
 'shared' qualifiers in the last error message.

 shared(void delegate(shared(SocketListener)) shared)

 1) The 'shared' in the middle: That one makes the delegate take 
 a shared(SocketListener) argument when it gets called.

 2) The 'shared' on the right-hand side: (I am not sure about 
 this one.) That one makes the context pointer of the delegate 
 'shared'. For example, the delegate can only be called on a 
 shared class object.

 3) The 'shared' on the left-hand side: That one makes the type 
 of the delegate shared so that e.g. such a delegate can be 
 passed between threads.

 That's what I understand.

 Ali

Jun 19 2014

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digitalmars.D.learn - Placement of shared does not allow to set a delegate