Greetings

I am facing problem passing a shared class method as an argument to a function. Look at the following minimized code snippet.

class Foo {
  shared // compiles when commented out
    void bar() {}
}

void frop(void delegate() dg) {
}

void main() {
  shared Foo foo = new shared(Foo);
  frop(&foo.bar);
}

I get the following errors (using dmd 2.052)
dg.d(11): Error: function dg.frop (void delegate() dg) is not callable using
argument types (void delegate() shared)
dg.d(11): Error: cannot implicitly convert expression (&foo.bar) of type
void delegate() shared to void delegate()

Please suggest a valid signature for the function frop, so that it can take shared delegates.

Regards
- Puneet

On 24/04/2011 15:40, d coder wrote:
> Greetings
>
> I am facing problem passing a shared class method as an argument to a
> function. Look at the following minimized code snippet.
>
> class Foo {
>    shared // compiles when commented out
>      void bar() {}
> }
>
> void frop(void delegate() dg) {
> }
>
> void main() {
>    shared Foo foo = new shared(Foo);
>    frop(&foo.bar);
> }
>
> I get the following errors (using dmd 2.052)
> dg.d(11): Error: function dg.frop (void delegate() dg) is not callable
> using argument types (void delegate() shared)
> dg.d(11): Error: cannot implicitly convert expression (&foo.bar) of type
> void delegate() shared to void delegate()
>
> Please suggest a valid signature for the function frop, so that it can
> take shared delegates.
>
> Regards
> - Puneet

I've copy and pasted my reply to Benjamin below, you should be able to adapt it to your needs:

The only way I've found to do this that works is using an alias - this is probably worth a bug report if there isn't one already.
----
class A
{
    // Note that you get forward reference errors if you opt to
    // infer the return type here. That's also a bug.
    void method(const const(char[]) str) shared
    {
    }
}

alias typeof(&A.method) shdg;

void foo(shdg foo)
{
}

void main()
{
    foo(&A.method);
}
----

-- 
Robert
http://octarineparrot.com/

>
>
> I've copy and pasted my reply to Benjamin below, you should be able to adapt it to your needs:
>

Stupid me. Should have checked the list before posting.


>
> The only way I've found to do this that works is using an alias - this is probably worth a bug report if there isn't one already.


I checked and found that this is already reported http://d.puremagic.com/issues/buglist.cgi?quicksearch=shared+delegate

And since Walter says that const issues are high on his priority list, I hope this would get resolved soon.

Regards
- Puneet