What is a “yield return” equivalent in the D programming language?

Question

Here is a simple generator in C#.

    IEnumerable Foo()
    {
        int a = 1, b = 1;
        while(true)
        {
            yield return b;
             


        

Answer 1

The std.concurrency module now has a Generator class which makes this even easier (and you don't need a third-party library).

The class is an input range, so it can be used with for loops and all the standard std.range/std.algorithm functions.

import std.stdio;
import std.range;
import std.algorithm;
import std.concurrency : Generator, yield;

void main(string[] args) {
    auto gen = new Generator!int({
        foreach(i; 1..10)
            yield(i);
    });

    gen
        .map!(x => x*2)
        .each!writeln
    ;
}