Full closures for D

[Martin d Anjou]

>>  It's not an optimal solution because the "does the function escape"
>>  heuristic captures too many functions.
>
> You could let the programmer specify explicitly whether or not to make a 
> function a closure or not, maybe with a key word or something.

A programming language called Vera uses the "shadow" keyword to acheive a 
somewhat related effect.

>From http://www.asic-world.com/vera/concurrency_control1.html:

program shadow_variable {
   spawn_process() ;
   delay(100) ;
   spawn_process_with_shawdow();
   delay(100) ;
}

task print(integer i) {
   printf("   n = %0d\n", i);
}

task spawn_process () {
   integer n;
   printf("In spawn_process\n");
   for(n=0; n<3 ; n++) {
     fork
       print(n) ;
     join none
   }
}

task spawn_process_with_shawdow () {
   shadow integer n;
   printf("In spawn_process_with_shadow_variable\n");
   for(n=0; n<3 ; n++) {
     fork
       print(n) ;
     join none
   }
}

Executing this code gives:
  In spawn_process
     n = 3
     n = 3
     n = 3
  In spawn_process_with_shadow_variable
     n = 0
     n = 1
     n = 2

I am not a language expert, but this seemed related.

Martin