Wingman for Haskell

"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. Just hover over a typed hole, run the "Attempt to fill hole" code action, et voila!

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:

" 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

" beta only
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, including pattern matching and recursion
• Automatic case-splitting --- just run the "Case split on " code action
• Smart next actions, for those times it can't read your mind

Support

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