advent-of-code2017

Stack

Stack is used to manage our project dependencies as well as to fetch GHC.

Setup

Install Stack:

curl -sSL https://get.haskellstack.org/ | sh

Install GHC:

stack setup

Make sure ~/.local/bin/ is on your $PATH.

More info here: https://docs.haskellstack.org/en/stable/README/

Install some common utils

The following commands are used by editor plugins and are pretty useful.

stack install intero
stack install stylish-haskell
stack install hlint

Editor Configuration

VS Code

I personally really like intero as it plays really nice with stack and has support in most major editors. For now I'll show vs code but there should be intero plugins for everything.

Install the following plugins:

• haskell-linter
• stylish-haskell
• hoogle-vscode
• haskero

REPL

Get a REPL:

stack ghci

Once inside a REPL you can load your module (after code changes):

:load Problem01

Get type information:

:t map

NOTE: In the REPL to define a new top level declaration you must do it like:

let foo = 3

Build & Run

stack build
stack exec advent-of-code2017

Automatic Build

stack build --file-watch

hpack

HPack is a new way of specifying dependencies that is a bit simpler than using cabal files which is the old build tool. Stack will auto generate a cabal file from package.yaml, so there is no need to edit it at all. New dependencies can be added to the package.yaml file. If stack can't resolve them then they can be specified in stack.yaml.