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digitalmars.D.learn - cannot have overloaded nested functions?

reply Timothee Cour <thelastmammoth gmail.com> writes:
why isn't this supported?

 void main(){
    void fun();
    void fun(int x);//Error: declaration fun is already defined
}
May 15 2013
next sibling parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
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
May 15 2013
next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
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
May 15 2013
prev sibling parent Timothee Cour <thelastmammoth gmail.com> writes:
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
May 16 2013
prev sibling next sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
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
May 16 2013
prev sibling next sibling parent Timothee Cour <thelastmammoth gmail.com> writes:
 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
May 16 2013
prev sibling parent Jonathan M Davis <jmdavisProg gmx.com> writes:
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
May 16 2013