Fibers and Ranges

[Ali Çehreli via Digitalmars-d]

On 10/04/2015 04:40 PM, Freddy wrote:
> ---
> import core.thread;
> import std.conv;
> import std.stdio;
>
> void formatStuff(P)(P put, int stuff)
> {
>      put("a");
>      put("b");
>      put("c");
>      put(stuff);
>      foreach (i; 0 .. 10)
>      {
>          put(i ^^ stuff);
>      }
> }
>
> auto formatRange(alias sub, T...)(T args)
> {
>      class FormatFiber : Fiber
>      {
>          string front_;
>          this()
>          {
>              super(&run);
>              popFront;
>          }
>
>          void run()
>          {
>              sub(this, args);
>          }
>
>          void opCall(T)(T t)
>          {
>              front_ = t.to!string;
>              yield;
>          }
>
>          void popFront()
>          {
>              call;
>          }
>
>      @property:
>          string front()
>          {
>              return front_;
>          }
>
>          bool empty()
>          {
>              return state != State.HOLD;
>          }
>      }
>
>      return new FormatFiber;
> }
>
> void main()
> {
>      writeln(formatRange!formatStuff(5));
> }
> ---
> Another Idea thoughts?

There is std.concurrency.Generator to expose yielded elements as a range:

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

alias FiberRange = std.concurrency.Generator;

void yieldString(T)(T arg)
{
     yield(arg.to!string);
}

void formatStuff(int stuff)
{
     yieldString("a");
     yieldString("b");
     yieldString("c");
     yieldString(stuff);
     foreach (i; 0 .. 10)
     {
         yieldString(i ^^ stuff);
     }
}

void main()
{
     auto stuff = new FiberRange!string(() => formatStuff(5));
     writeln(stuff);
}

Ali

P.S. D.learn might be a better newsgroup for this thread. :)