Re: [RFA] handling of 'operator' in cp_find_first_component

[Daniel Berlin <dberlin@dberlin.org>]

On Monday, April 21, 2003, at 11:21  PM, Daniel Jacobowitz wrote:

>
> i.e. you can't have a program with
>   int foo<int> (int)
> and
>   long foo<int> (int)
> in it!


Stop right here.

This is not quite right, since the second example is invalid.
You can, however,  have (geez i haven't written C++ templates in a 
while. it took me a few compiles to get this right):

template <class blah> blah foo (int a)
{
         return a;
}
int main(void)
{
         int q = foo<int>(5);
         long r = foo<long>(5);
}

Note the only real difference here is in return type.
It also definitely generates two functions:
root@dberlin root]# nm -C a.o
          U __gxx_personality_v0
00000000 T main
00000000 W int foo<int>(int)
00000000 W long foo<long>(int)
[root@dberlin root]#

There is no way to write exactly what you want in valid C++ (IIRC), so 
i'm not sure if this program demonstrates what you think can't be done 
or not.

To answer whether you need the return type, let's add two 
specializations here and make it worse:
template <> long foo (int a)
{
	return 9;
}
template <> int foo (int a)
{
	return 10;
}

Now, without the return type in the template, you would *never* know 
which function to call from a debugger if someone does p foo(5) 
(However, i'll note the only case you will know is when someone does 
something like p a=foo(5), where "a" is a program variable of type int 
or long).
With the return type,  you could at least present a useful list to the 
user and ask.
Unless you want the list to have to re-demangle names so it can get the 
return type out again, or something ugly like that.

--Dan