Full closures for D

[BCS]

Craig Black wrote:
> "Mikola Lysenko" <mclysenk at mtu.edu> wrote in message 
> news:fgns3v$1b13$1 at digitalmars.com...
> 
>>I'm excited.  For the first time it is now possible to do futures in 7 
>>lines of code:
>>
>>T delegate() future(T)(lazy T expr)
>>{
>>   T res;
>>   auto t = new Thread({res = expr();});
>>   t.start;
>>   return { t.wait; return res; }
>>}
>>
>>
>>Which could then be used as follows:
>>
>>auto hard_result = future( hard_expression );
>>
>>// Do stuff ...
>>
>>use_result(hard_result());
>>
> 
> 
> Very cool stuff!  Did you test this code to see if it actually works?
> 
> A little off topic, but I was looking at your code and wondering if "lazy" 
> always means that the expression becomes a delegate?  When a template is 
> used, the compiler could embed the expression directly rather than creating 
> a delegate.  Since D is big on compile-time optimization, I was wondering if 
> it does this.
> 
> -Craig 
> 
> 

string mixins are fun:

typeof(mixin(expr)) delegate() future(char[] expr)()
{
    typeof(mixin(expr)) res;
    auto t = new Thread({res = mixin(expr);});
    t.start;
    return { t.wait; return res; }
}

auto hard_result = future!("hard_expression");
// Do stuff ...
use_result(hard_result());


NOTE: this runs into the issue that there is no way to get a template to 
play with the local variables of a function. If there were a way to do 
this I can think of a number of very cool things that could be done.