Threading challenge: calculate fib(45) while spinning

[Ali Çehreli]

On 10/14/21 8:35 PM, jfondren wrote:
> The book, "The Go Programming Language" has this simple goroutine example:

Here is one that uses receiveTimeout and OwnerTerminated:

import std.stdio;
import std.concurrency;
import core.thread;

void main() {
   spawnLinked(&spinner, 100.msecs);
   enum n = 45;
   const fibN = fib(n); // slow
   writefln!"\rFibonacci(%d) = %d"(n, fibN);
}

void spinner(const(Duration) delay) {
   for (;;) {
     foreach (r; `-\|/`) {
       writef!"\r%c"(r);
       stdout.flush();
       bool done;
       receiveTimeout(delay,
                      (OwnerTerminated msg) {
                        done = true;
                      });
       if (done) {
         return;
       }
     }
   }
}

auto fib(int x) {
   if (x < 2) {
     return x;
   }
   return fib(x-1) + fib(x-2);
}

Ali