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#future

Futures are values yet to be computed. They are shared and thread-safe.

Futures receive a pending value with fulfill, and can actively forward the received value to callback delegates registered with onFulfill.

If f :: A -> B, then async!f :: A -> Future!(Result!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.isPending.

If f succeeds, c.isReady and b == c.result.success.

If f throws, c.isReady and c.result.failure is inhabited with the caught error.

Attempting to read c.result before c.isReady 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.

For a futures a and b, and arguments c...

a.then!f(c) returns a future which contains f(a.result, c) when a is ready

a.next!f(c) chains two futures (a and f(a.result, c)) into a single future

if a.result is also a future, sync(a) joins the inner and outer futures of a (like a lazy await.result.await)

when(a,b) is a future Tuple(a.result, b.result), ready when both a and b are ready

race(a,b) is a future Union(a.result, b.result), ready when either a or b are ready

is contained in the unittest

dependency "future" version="0.1.0"