Chapter 0: Before You Start

These are the tutorial notes for the ReWire language.

Prerequisites

Haskell

There's no way of learning ReWire without knowing basic Haskell. I'm a Mac guy so I would use homebrew as in

• brew install ghc. This will install the Glasgow Haskell Compiler.
• brew install stack. Stack is a tool for installing haskell packages. It really makes things easy (well, easier).

Installing ReWire

ReWire is freely available. Here is the repository where you find the most recent version: ReWire source. Follow the directions -- stack makes it easy.

• This installation will build the ReWire compiler rwc and
• Install libraries (aka ReWire-user) that allow you to program in ReWire with the Haskell interpreter ghci.

Monads in Haskell

You have to be comfortable with the basics of "monad wrangling". You don't need to understand them in any great depth, but understanding the following ought to do:

1. The Identity monad;
2. the state monad; and
3. the Maybe monad.

Understanding the basic usage of the StateT monad transformer is important. It's a shame that they are known as "transformer" instead of "constructor", because all a monad transformer is is a way to construct monads in a canonical fashion.

Monads are a concept from Category Theory. I love Category Theory, really I do. But I'd strongly recommend avoiding categorical treatments of monads if this is your first time with this material. Rather, check out Graham Hutton or Miran Lipovaca's texts as they're both excellent.

Reactive Resumption Monads

These are a particular family of monads that can be used to precisely describe synchronous concurrency (e.g., like clocked computations in hardware). They sound scary, but they're not. Check out the following papers of mine for the basics if you want. I suspect a lot of readers will just look at its usage in ReWire and get them well enough.

1. Essence of Multitasking and
2. Cheap (But Functional) Threads.

These monads are implemented in the Hackage package monad-resumption.