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November 03, 2007
Forward reference to enum nested in a class
Dear Everyone,

I have problem on reference to enum nested in a class from template difinition.


class Foo
{
	enum FooEnum {}
}
enum GlobalEnum {}

class BarA(Foo.FooEnum T) {} // Error, Foo.FooEnum is forward referenced
class BarB(T : GlobalEnum){} // OK
class BarC
{
	FooEnum t; // OK
}


I want to specialize class template BarA in each conditions listed in Foo.FooEnum closely related with class Foo.
This trial, however, failed because of forward reference to Foo.FooEnum from BarA.
I have avoided this problem in this way:


enum FooEnum {}
class Foo
{
	alias .FooEnum FooEnum;
}
class BarD(Image.FooEnum T) {}


Please let me know the way to resolve this probrem.
I have no idea whether this problem should be avoided by such way or another.



Sincerely,
November 04, 2007
Re: Forward reference to enum nested in a class
"HOSOKAWA Kenchi" <hskwk@inter7.jp> wrote in message 
news:fghd88$2eql$1@digitalmars.com...
> Dear Everyone,
>
> I have problem on reference to enum nested in a class from template 
> difinition.
>
>
> class Foo
> {
> enum FooEnum {}
> }
> enum GlobalEnum {}
>
> class BarA(Foo.FooEnum T) {} // Error, Foo.FooEnum is forward referenced
> class BarB(T : GlobalEnum){} // OK
> class BarC
> {
> FooEnum t; // OK
> }
>
>
> I want to specialize class template BarA in each conditions listed in 
> Foo.FooEnum closely related with class Foo.
> This trial, however, failed because of forward reference to Foo.FooEnum 
> from BarA.
> I have avoided this problem in this way:
>
>
> enum FooEnum {}
> class Foo
> {
> alias .FooEnum FooEnum;
> }
> class BarD(Image.FooEnum T) {}
>
>
> Please let me know the way to resolve this probrem.
> I have no idea whether this problem should be avoided by such way or 
> another.

It's a bug that's been in the language as long as I can remember.  Walter 
deems it "too difficult to fix with too little reward."  BS, I say.
November 06, 2007
Re: Forward reference to enum nested in a class
Jarrett Billingsley Wrote:

> "HOSOKAWA Kenchi" <hskwk@inter7.jp> wrote in message 
> news:fghd88$2eql$1@digitalmars.com...
> > Dear Everyone,
> >
> > I have problem on reference to enum nested in a class from template 
> > difinition.
> >
> >
> > class Foo
> > {
> > enum FooEnum {}
> > }
> > enum GlobalEnum {}
> >
> > class BarA(Foo.FooEnum T) {} // Error, Foo.FooEnum is forward referenced
> > class BarB(T : GlobalEnum){} // OK
> > class BarC
> > {
> > FooEnum t; // OK
> > }
> >
> >
> > I want to specialize class template BarA in each conditions listed in 
> > Foo.FooEnum closely related with class Foo.
> > This trial, however, failed because of forward reference to Foo.FooEnum 
> > from BarA.
> > I have avoided this problem in this way:
> >
> >
> > enum FooEnum {}
> > class Foo
> > {
> > alias .FooEnum FooEnum;
> > }
> > class BarD(Image.FooEnum T) {}
> >
> >
> > Please let me know the way to resolve this probrem.
> > I have no idea whether this problem should be avoided by such way or 
> > another.
> 
> It's a bug that's been in the language as long as I can remember.  Walter 
> deems it "too difficult to fix with too little reward."  BS, I say. 
> 
> 

Thank you very much for the information.
Fortunately I have a alternative solution written above, so I won't care of this problem.

again, thanks.
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