simple_future ~master

simple_future

Provides a (very) simple async function combinator.

If f :: A -> B, then async!f :: A -> Future!B. Suppose f(a) = b and async!f(a) = c.

async!f will execute f in a separate thread when invoked.

While f is being computed, c.pending.

If f succeeds, c.completed and b == c.result.

If f throws, c.failed.

Attempting to read c.result before c.completed is an error.

async!f can be made blocking at any time with c.await.

For convenience, c.await returns c so that c.await.result == c.result.

Note that, for async!f, f must be public so that the async template can see it. To lift a non-publicly-visible function g :: A -> B, use the non-template async(g, a).