why isn't this supported?

 void main(){
    void fun();
    void fun(int x);//Error: declaration fun is already defined
}

On Wed, 15 May 2013 19:10:49 -0400, Timothee Cour <thelastmammoth@gmail.com> wrote:

> why isn't this supported?
>
>  void main(){
>     void fun();
>     void fun(int x);//Error: declaration fun is already defined
> }

Don't know, but it hasn't been supported ever.  Spec clearly states it's not supported, but not why.  I suppose it is not difficult to name it something else?

Note that there are a lot of different rules with nested functions that don't apply to normal functions.

-Steve

On Wednesday, May 15, 2013 20:48:19 Steven Schveighoffer wrote:
> On Wed, 15 May 2013 19:10:49 -0400, Timothee Cour
> 
> <thelastmammoth@gmail.com> wrote:
> > why isn't this supported?
> > 
> >  void main(){
> > 
> >     void fun();
> >     void fun(int x);//Error: declaration fun is already defined
> > 
> > }
> 
> Don't know, but it hasn't been supported ever.  Spec clearly states it's not supported, but not why.  I suppose it is not difficult to name it something else?
> 
> Note that there are a lot of different rules with nested functions that don't apply to normal functions.

You can't have multiple instantiations of templated nested functions either. IIRC, I created a bug report on it, and Walter closed it as won't fix, but I don't remember what his reasoning was, though IIRC, he was essentially of the opinion that nested functions didn't need to have the full capabilities of normal functions. I assume that that simplifies their implementation, but I don't know.

- Jonathan M Davis

at the very least (or until it gets fixed) dmd should emit a more friendly
error message:
'cannot overload a function in a nested scope'
otherwise this is hard to understand.

On Wed, May 15, 2013 at 11:43 PM, Jonathan M Davis <jmdavisProg@gmx.com>wrote:

> On Wednesday, May 15, 2013 20:48:19 Steven Schveighoffer wrote:
> > On Wed, 15 May 2013 19:10:49 -0400, Timothee Cour
> >
> > <thelastmammoth@gmail.com> wrote:
> > > why isn't this supported?
> > >
> > >  void main(){
> > >
> > >     void fun();
> > >     void fun(int x);//Error: declaration fun is already defined
> > >
> > > }
> >
> > Don't know, but it hasn't been supported ever.  Spec clearly states it's not supported, but not why.  I suppose it is not difficult to name it something else?
> >
> > Note that there are a lot of different rules with nested functions that don't apply to normal functions.
>
> You can't have multiple instantiations of templated nested functions
> either.
> IIRC, I created a bug report on it, and Walter closed it as won't fix, but
> I
> don't remember what his reasoning was, though IIRC, he was essentially of
> the
> opinion that nested functions didn't need to have the full capabilities of
> normal functions. I assume that that simplifies their implementation, but I
> don't know.
>
> - Jonathan M Davis
>

On Thursday, May 16, 2013 00:28:15 Timothee Cour wrote:
> at the very least (or until it gets fixed) dmd should emit a more friendly
> error message:
> 'cannot overload a function in a nested scope'
> otherwise this is hard to understand.

I don't know what else it would say. It means exactly what it says. It's telling you exactly what it can't do. Sure, it isn't telling you _why_ it's illegal, but error messages don't usually say that sort of thing anyway. So, if you have a good suggestion as to improve the error message, please create an enhancement request for it, but as far as I can tell, it means exactly what it says, and I don't know how it could be friendlier.

- Jonathan M Davis

> as far as I can tell, it means exactly what it says, and I don't know how
it could be friendlier.

the error message 'declaration fun is already defined' is surprising because 'void fun(int x);' and 'void fun();' are typically 2 different function declarations, having different signatures. So this this sounds misleading/surprising.

> if you have a good suggestion as to improve the error message, please
create an enhancement request for it

how about:

'cannot overload a function in a nested scope'

On Thu, May 16, 2013 at 12:35 AM, Jonathan M Davis <jmdavisProg@gmx.com>wrote:

> On Thursday, May 16, 2013 00:28:15 Timothee Cour wrote:
> > at the very least (or until it gets fixed) dmd should emit a more
> friendly
> > error message:
> > 'cannot overload a function in a nested scope'
> > otherwise this is hard to understand.
>
> I don't know what else it would say. It means exactly what it says. It's
> telling you exactly what it can't do. Sure, it isn't telling you _why_ it's
> illegal, but error messages don't usually say that sort of thing anyway.
> So,
> if you have a good suggestion as to improve the error message, please
> create
> an enhancement request for it, but as far as I can tell, it means exactly
> what
> it says, and I don't know how it could be friendlier.
>
> - Jonathan M Davis
>

On Thursday, May 16, 2013 01:15:06 Timothee Cour wrote:
> > as far as I can tell, it means exactly what it says, and I don't know how
> 
> it could be friendlier.
> 
> the error message 'declaration fun is already defined' is surprising because 'void fun(int x);' and 'void fun();' are typically 2 different function declarations, having different signatures. So this this sounds misleading/surprising.
> 
> > if you have a good suggestion as to improve the error message, please
> 
> create an enhancement request for it
> 
> how about:
> 
> 'cannot overload a function in a nested scope'

Sounds fine to me. Open an enhancement request for it.

- Jonathan M Davis