HACKING.md

Development guide

Build

To build a development version, install cabal and ghc and run:

$ git clone https://github.com/owo-lang/OwO
$ cd OwO
$ cabal install alex
$ cabal install

You can also use stack, no problem:

$ git clone https://github.com/owo-lang/OwO
$ cd OwO
$ stack install alex
$ stack install

To install bash completions temporarily, run:

$ source <(owo --bash-completion-script $(which owo))

To install bash completions for all users permanently, run:

$ owo --bash-completion-script $(which owo) >> owo_completion
$ sudo mv owo_completion /etc/.bash_completion.d/

You can run hlint with this command:

$ hlint src

Testing

The tests are split into two parts -- Haskell tests and golden-valued tests. This is because stack is too powerful on Windows.

Golden-valued tests

You need perl5 > v5.10 and a bash environment to run golden-valued tests. For Windows, you can use git-bash. It works like a charm.

See this instruction.

Coding convention

• Functions/record projections should be camelCase

• The prefix Psi stands for Program Structure Item, it's for concrete syntax elements

  • contextual syntax errors can be detected here

• The prefix Ast stands for Abstract Syntax Tree, it's for abstract syntax tree

  • no syntactic sugars
  • no unresolved references

Setup your editor

IntelliJ-Haskell

You're basically all set.

Code

Install the stylish-haskell extension to format the code easier. You should always format your code before pushing it.

It's recommended to use drammie's Simple GHC (Haskell) Integration plugin. Configure your workspace:

{
    "ghcSimple.workspaceType": "stack"
}

You can also install the extension Run On Save to simply run the formatter on saving your *.hs file, by giving such commands in settings:

{
    "emeraldwalk.runonsave": {
        "commands": [
            {
                "match": "\\.hs$",
                "cmd": "stylish-haskell -i ${file}"
            }
        ]
    }
}

Emacs

You should have stylish-haskell installed:

$ cabal install stylish-haskell

Then, add this to your .emacs file:

(custom-set-variables
 '(haskell-stylish-on-save t))

So that you can format your code when you save them.