static static

[Yigal Chripun]

bearophile wrote:
> Yigal Chripun:
> 
>> Regardless of usefulness (or good design) of such variables, this sounds
>> extremely dangerous. The compiler must not change semantics of the
>> program based on optimization. optimizing away such variables most
>> definitely alters the semantics.
> 
> Maybe you have misunderstood, or I have explained the things badly. So I explain again.
> 
> I have seen that LDC (when it performs link-time optimization, that's not done in all situations) keeps just one copy of constants inside the binary even if such constants are present in more than one template instance. In the situations where LTO is available I think this doesn't cause problems.
> 
> Then I am half-seriously proposing a syntax like:
> T foo(T)(T x) {
>   static static int y;
>   // ...
> }
> 
> Where the y is now static to (shared among) all instances of the templated function foo. This may be a little error-prone and maybe not that useful, but again here the compiler doesn't change the semantics of the program, because using a double static keyword the programmer has stated such intention.
> 
> Bye,
> bearophile

Oh. ok. I seems I completely misunderstood you. It wasn't clear to me 
before that your were talking about constants. Of course it's perfectly 
OK to optimize _constants_ like that.

IMO, static is harmful and should be avoided. some newer languages 
recognize this and completely remove this from the language. I'd like to 
see D going in that path rather than adding even more ways to use static.

regarding your concrete proposal - as others said, you can use global 
variables for that or put this inside a struct if you want to limit the 
scope.