hls-tactics-plugin-1.2.0.0: README.md

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<img src="https://haskellwingman.dev/wingman.png" height="256" alt="Wingman for Haskell" title="Wingman for Haskell">
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<p>&nbsp;</p>

# Wingman for Haskell

[![Hackage](https://img.shields.io/hackage/v/hls-tactics-plugin.svg?logo=haskell&label=hls-tactics-plugin)](https://hackage.haskell.org/package/hls-tactics-plugin)

"Focus on the important stuff; delegate the rest"


## Dedication

> There's a lot of automation that can happen that isn't a replacement of
> humans, but of mind-numbing behavior.
>
> --Stewart Butterfield


## Overview

Wingman writes the boring, auxiliary code, so you don't have to. Generate
functions from type signatures, and intelligently complete holes.


## Getting Started

Wingman for Haskell is enabled by default in all [official release of Haskell
Language Server.][hls] Just hover over a typed hole, run the "Attempt to
fill hole" code action, *et voila!*

[hls]: https://github.com/haskell/haskell-language-server/releases


## Editor Configuration

### Enabling Jump to Hole

Set the `haskell.plugin.tactics.config.hole_severity` config option to `4`, or
`hint` if your editor uses a GUI for its configuration. This has the potential
to negatively impact performance --- please holler if you notice any appreciable
slowdown by enabling this option.


### coc.nvim

The following vimscript maps Wingman code-actions to your leader key:

```viml
" use [h and ]h to navigate between holes
nnoremap <silent> [h :<C-U>call CocActionAsync('diagnosticPrevious', 'hint')<CR>
nnoremap <silent> ]h :<C-U>call <SID>JumpToNextHole()<CR>

" <leader>d to perform a pattern match, <leader>n to fill a hole
nnoremap <silent> <leader>d  :<C-u>set operatorfunc=<SID>WingmanDestruct<CR>g@l
nnoremap <silent> <leader>n  :<C-u>set operatorfunc=<SID>WingmanFillHole<CR>g@l
nnoremap <silent> <leader>r  :<C-u>set operatorfunc=<SID>WingmanRefine<CR>g@l
nnoremap <silent> <leader>c  :<C-u>set operatorfunc=<SID>WingmanUseCtor<CR>g@l
nnoremap <silent> <leader>a  :<C-u>set operatorfunc=<SID>WingmanDestructAll<CR>g@l


function! s:JumpToNextHole()
  call CocActionAsync('diagnosticNext', 'hint')
endfunction

function! s:GotoNextHole()
  " wait for the hole diagnostics to reload
  sleep 500m
  " and then jump to the next hole
  normal 0
  call <SID>JumpToNextHole()
endfunction

function! s:WingmanRefine(type)
  call CocAction('codeAction', a:type, ['refactor.wingman.refine'])
  call <SID>GotoNextHole()
endfunction

function! s:WingmanDestruct(type)
  call CocAction('codeAction', a:type, ['refactor.wingman.caseSplit'])
  call <SID>GotoNextHole()
endfunction

function! s:WingmanDestructAll(type)
  call CocAction('codeAction', a:type, ['refactor.wingman.splitFuncArgs'])
  call <SID>GotoNextHole()
endfunction

function! s:WingmanFillHole(type)
  call CocAction('codeAction', a:type, ['refactor.wingman.fillHole'])
  call <SID>GotoNextHole()
endfunction

function! s:WingmanUseCtor(type)
  call CocAction('codeAction', a:type, ['refactor.wingman.useConstructor'])
  call <SID>GotoNextHole()
endfunction
```

### Other Editors

Please open a PR if you have a working configuration!


## Features

* [Type-directed code synthesis][auto], including pattern matching and recursion
* [Automatic case-splitting][case] --- just run the "Case split on <x>" code action
* [Smart next actions][next], for those times it can't read your mind

[auto]: https://haskellwingman.dev/foldr.gif
[case]: https://haskellwingman.dev/case-split.gif
[next]: https://haskellwingman.dev/intros.gif


## Support

Please consider [pledging on Patreon][patreon] to support the project and get
access to cutting-edge features.

[patreon]: https://www.patreon.com/wingman_for_haskell