This is an analysis of how variadic generics could be added to Rust. It's not a proposal so much as a summary of existing work, and a toolbox for creating an eventual proposal.
Variadic generics (aka variadic templates, or variadic tuples), are an often-requested feature that would enable traits, functions and data structures to be generic over a variable number of types.
To give a quick example, a Rust function with variadic generics might look like this:
Author: Chris Lattner
Modern Cocoa development involves a lot of asynchronous programming using closures and completion handlers, but these APIs are hard to use. This gets particularly problematic when many asynchronous operations are used, error handling is required, or control flow between asynchronous calls gets complicated. This proposal describes a language extension to make this a lot more natural and less error prone.
This paper introduces a first class Coroutine model to Swift. Functions can opt into to being async, allowing the programmer to compose complex logic involving asynchronous operations, leaving the compiler in charge of producing the necessary closures and state machines to implement that logic.