I have a pull request to merge ghc-imported-from into ghc-mod. The main benefit of being part of ghc-mod is that I don’t have to duplicate ghc-mod’s infrastructure for handling sandboxes, GHC options, interfaces to other build tools like Stack, and compatibility with more versions of GHC.
The pull request is still under review, so until then you can try it out by cloning the development branches:
git clone -b imported-from https://github.com/DanielG/ghc-mod.git ghc-mod-imported-from
cd ghc-mod-imported-from
cabal update && cabal sandbox init && cabal install
export PATH=`pwd`/.cabal-sandbox/bin:$PATH
Assuming that you use Plugged for managing Vim/Neovim plugins, use my branch of ghcmod-vim by adding this to your vimrc:
call plug#begin('~/.vim/plugged')
Plug 'carlohamalainen/ghcmod-vim', { 'branch': 'ghcmod-imported-from-cmd', 'for' : 'haskell' }
Install the plugin with :PlugInstall in vim.
Here are some handy key mappings:
au FileType haskell nnoremap :GhcModType
au FileType haskell nnoremap :GhcModInfo
au FileType haskell nnoremap :GhcModTypeClear
au FileType lhaskell nnoremap :GhcModType
au FileType lhaskell nnoremap :GhcModInfo
au FileType lhaskell nnoremap :GhcModTypeClear
au FileType haskell nnoremap :GhcModOpenDoc
au FileType lhaskell nnoremap :GhcModOpenDoc
au FileType haskell nnoremap :GhcModDocUrl
au FileType lhaskell nnoremap :GhcModDocUrl
au FileType haskell vnoremap :GhcModOpenHaddockVismode
au FileType lhaskell vnoremap :GhcModOpenHaddockVismode
au FileType haskell vnoremap :GhcModEchoUrlVismode
au FileType lhaskell vnoremap :GhcModEchoUrlVismode
On the command line, use the imported-from command. It tells you the defining module, the exporting module, and the Haddock URL:
$ ghc-mod imported-from Foo.hs 9 34 show
base-4.8.2.0:GHC.Show.show Prelude https://hackage.haskell.org/package/base-4.8.2.0/docs/Prelude.html
From Vim/Neovim, navigate to a symbol and hit F4 which will open the Haddock URL in your browser, or F5 to echo the command-line output.
