Here is my proposal for syntax support for the existing callback+libdispatch patterns: <a href="https:&#x2F;&#x2F;gist.github.com&#x2F;oleganza&#x2F;7342ed829bddd86f740a#async-semantics" rel="nofollow">https:&#x2F;&#x2F;gist.github.com&#x2F;oleganza&#x2F;7342ed829bddd86f740a#async-...</a><p>The idea is to flatten the syntax without change of the runtime model in the same spirit they did error handling: feels like exceptions, but without ugly stack manipulations.