Vim

This page is intended for Haskell vim-users.

Indentation

The following setup from merijn @ #haskell ensures you use spaces not tabs for indentation for generally sane behaviour:

" Tab specific option
set tabstop=8                   "A tab is 8 spaces
set expandtab                   "Always uses spaces instead of tabs
set softtabstop=4               "Insert 4 spaces when tab is pressed
set shiftwidth=4                "An indent is 4 spaces
set shiftround                  "Round indent to nearest shiftwidth multiple

Plugins

Put code in file ~/.vim/plugin/Haskell.vim, or in multiple files in that directory.

Module Sections

The following code prompts for a name, and places a section with that name at current position, when key sequence "--s":

let s:width = 80

function! HaskellModuleSection(...)
    let name = 0 < a:0 ? a:1 : inputdialog("Section name: ")

    return  repeat('-', s:width) . "\n"
    \       . "--  " . name . "\n"
    \       . "\n"

endfunction

nmap <silent> --s "=HaskellModuleSection()<CR>gp

Like so:

--------------------------------------------------------------------------------
--  my section

Module Headers

The following code prompts for module name, a note, a description of module, and places a module comment at top, when key sequence "--h":

let s:width = 80


function! HaskellModuleHeader(...)
    let name = 0 < a:0 ? a:1 : inputdialog("Module: ")
    let note = 1 < a:0 ? a:2 : inputdialog("Note: ")
    let description = 2 < a:0 ? a:3 : inputdialog("Describe this module: ")
    
    return  repeat('-', s:width) . "\n" 
    \       . "-- | \n" 
    \       . "-- Module      : " . name . "\n"
    \       . "-- Note        : " . note . "\n"
    \       . "-- \n"
    \       . "-- " . description . "\n"
    \       . "-- \n"
    \       . repeat('-', s:width) . "\n"
    \       . "\n"

endfunction


nmap <silent> --h "=HaskellModuleHeader()<CR>:0put =<CR>

like so:

--------------------------------------------------------------------------------
-- | 
-- Module      : MyModule
-- Note        : This is a preview
-- 
-- This is an empty module, to show the headercomment produced. 
-- 
--------------------------------------------------------------------------------

List of Plugins

• haskell-vim

Quote from [1]:

It’s the filetype plugin for Haskell that should ship with Vim.

• Ale (Asynchronous Linting Engine)

ALE (Asynchronous Lint Engine) is a plugin for providing linting (checking syntax and semantics) in NeoVim 0.2.0+ and Vim 8 while you edit your text files, and acts as a Vim Language Server Protocol client.

Comes with linters cabal_ghc, ghc, ghc_mod, hdevtools, hie, hlint, stack_build, stack_ghc

• Hdevtools taken from the github page:

hdevtools is a command line program powered by the GHC API, that provides services for Haskell development. hdevtools works by running a persistent process in the background, so that your Haskell modules remain in memory, instead of having to reload everything each time you change only one file. This is just like :reload in GHCi - with hdevtools you get the speed of GHCi as well as tight integration with your editor.

This is the Vim plugin that integrates Vim with hdevtools.