Syntax Highlighting and Indentation for Haskell and Cabal
=========================================================

I was unhappy with the Haskell scripts that are
shipped with vim, therefore I decided to make my
own based on [idris-vim][].

I hope you find this useful.

![Screenshot](http://raichoo.github.io/images/haskell-vim.png)

## Features

* Covers a broader spectrum of keywords
* Highlighting for new features like type families, pattern synonyms, arrow syntax, recursive do, role annotations, QuasiQuotation
* More contextual highlighting (e.g. highlight 'as' or 'family' only in appropriate places)
* Smarter indentation
* Better Cabal support

## Installation

I recommend using [Pathogen][] for installation. Simply clone
this repo into your `~/.vim/bundle` directory and you are ready to go.

    cd ~/.vim/bundle
    git clone https://github.com/neovimhaskell/haskell-vim.git

Be sure that the following lines are in your
`.vimrc`


    syntax on
    filetype plugin indent on

### Manual Installation

Copy content into your `~/.vim` directory.

## Configuration

### Features

To enable the features you would like to use, just add the according line to your
`.vimrc`.

```viml
let g:haskell_enable_quantification = 1   " to enable highlighting of `forall`
let g:haskell_enable_recursivedo = 1      " to enable highlighting of `mdo` and `rec`
let g:haskell_enable_arrowsyntax = 1      " to enable highlighting of `proc`
let g:haskell_enable_pattern_synonyms = 1 " to enable highlighting of `pattern`
let g:haskell_enable_typeroles = 1        " to enable highlighting of type roles
let g:haskell_enable_static_pointers = 1  " to enable highlighting of `static`
let g:haskell_backpack = 1                " to enable highlighting of backpack keywords
```

### Highlighting

`haskell-vim` has an opinionated highlighting. If you do not like that you can switch to
a more traditional mode by setting `g:haskell_classic_highlighting` to `1`.

Disabling Template Haskell and Quasiquoting syntax is possible by setting
`g:haskell_disable_TH` to `1`.

### Indentation

To configure indentation in `haskell-vim` you can use the following variables to change indentation depth, just add the according line to your `.vimrc`.

If you dislike how indentation works you can disable it by setting `g:haskell_indent_disable` to
`1`.

Additionally you can use the
[vim-hindent](https://github.com/alx741/vim-hindent) plugin to achieve automatic
indentation using *hindent*.

#### Haskell

* `let g:haskell_indent_if = 3`

        if bool
        >>>then ...
        >>>else ...

* `let g:haskell_indent_case = 2`

        case xs of
        >>[]     -> ...
        >>(y:ys) -> ...

* `let g:haskell_indent_let = 4`

        let x = 0 in
        >>>>x

* `let g:haskell_indent_where = 6`

        where f :: Int -> Int
        >>>>>>f x = x

* `let g:haskell_indent_before_where = 2`

        foo
        >>where

* `let g:haskell_indent_after_bare_where = 2`

        where
        >>foo

* `let g:haskell_indent_do = 3`

        do x <- a
        >>>y <- b

* `let g:haskell_indent_in = 1`

        let x = 1
        >in x

* `let g:haskell_indent_guard = 2`

        f x y
        >>|

`haskell-vim` also supports an alterative style for `case` indentation.

* `let g:haskell_indent_case_alternative = 1`

        f xs ys = case xs of
        >>[]     -> ...
        >>(y:ys) -> ...


#### Cabal

*  `let g:cabal_indent_section = 2` (limited to max. 4 spaces)

        executable name
        >>main-is:             Main.hs


[Pathogen]: https://github.com/tpope/vim-pathogen
[idris-vim]: https://github.com/idris-hackers/idris-vim