Haskell Tool Stack awareness

README.md

@@ -2,13 +2,13 @@ hdevtools Vim Plugin
 ====================
 
 Vim plugin for Haskell development powered by the lightning fast
-[hdevtools](<https://github.com/bitc/hdevtools/>) background server.
+[hdevtools](<https://github.com/hdevtools/hdevtools/>) background server.
 
 
 About
 -----
 
-[hdevtools](<https://github.com/bitc/hdevtools/>) is a command line program
+[hdevtools](<https://github.com/hdevtools/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
@@ -19,25 +19,60 @@ editor.
 This is the Vim plugin that integrates Vim with hdevtools.
 
 
-Installation
+Requirements
 ------------
 
-1. You must install the `hdevtools` command line program, It can be found
-   here: <https://github.com/bitc/hdevtools/>, or from Hackage:
+The *vim-hdevtools* plugin requires a way to run `hdevtools`. Here are the
+ways to make `hdevtools` available to the plugin.
+
+### Global `hdevtools`
+
+Install the `hdevtools` command line program so that it is on your
+executable `$PATH`.
+
+Get it from Github: <https://github.com/hdevtools/hdevtools/>
+
+Or from Hackage:
+
+    $ cabal install hdevtools
+
+Or from Stackage:
+
+    $ stack install hdevtools
+
+Note that `hdevtools` must be built with the same version of GHC as the
+project which you will be editing.
 
-        $ cabal install hdevtools
+### Local `hdevtools` with `stack`
 
-2. Install this plugin. [pathogen.vim](<https://github.com/tpope/vim-pathogen/>)
+If your project is built with [stack](<https://www.haskellstack.org>) and
+if you run Vim from the directory that contains `stack.yaml`, then
+the *vim-hdevtools* plugin can employ `stack` to automatically install
+`hdevtools` built with the same version of GHC indicated by the resolver
+in your `stack.yaml`. This will not conflict with any other installations
+of `hdevtools` on your system.
+
+If you want the *vim-hdevtools* plugin to use `stack`,
+you have to enable this feature in your `.vimrc` like so:
+
+    let g:hdevtools_stack = 1
+
+
+Installation
+------------
+
+1. Install this plugin. [pathogen.vim](<https://github.com/tpope/vim-pathogen/>)
    is the recommended way:
 
         cd ~/.vim/bundle
         git clone https://github.com/bitc/vim-hdevtools.git
 
-3. Configure your keybindings in your `.vimrc` file. I recommend something
+2. Configure your keybindings in your `.vimrc` file. I recommend something
    like:
 
         au FileType haskell nnoremap <buffer> <F1> :HdevtoolsType<CR>
-        au FileType haskell nnoremap <buffer> <silent> <F2> :HdevtoolsClear<CR>
+        au FileType haskell nnoremap <buffer> <silent> <F2> :HdevtoolsInfo<CR>
+        au FileType haskell nnoremap <buffer> <silent> <F3> :HdevtoolsClear<CR>
 
 
 Features
@@ -61,6 +96,9 @@ The type for the expression under the cursor will be printed, and the
 expression will be highlighted. Repeated presses will expand the expression
 that is examined.
 
+To get information from GHC about the identifier under cursor,
+execute `HdevtoolsInfo` (or press the `<F2>` key as configured above).
+
 You can execute `HdevtoolsClear` to get rid of the highlighting.
 
 Customization
@@ -79,6 +117,12 @@ appropriate (such as your project's `Session.vim`):
 Make sure that each GHC option has its own `-g` prefix (don't group multiple
 options like this: `"-g-isrc\ -Wall"`)
 
+I recommend setting the flag to
+[defer GHC type errors to runtime](<https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#deferring-type-errors-to-runtime>),
+so that Haskell expressions can be typechecked even if type errors
+elsewhere in the project would otherwise prevent GHC from compiling.
+
+    let g:hdevtools_options = '-g-fdefer-type-errors'
 
 Credits
 -------

autoload/hdevtools.vim

@@ -477,18 +477,15 @@ function! s:on_leave()
 endfunction
 
 function! hdevtools#build_command(command, args)
-  let l:cmd = 'hdevtools'
-  let l:cmd = l:cmd . ' ' . a:command . ' '
-
+  let l:cmd = g:hdevtools_exe . ' ' . a:command . ' '
   let l:cmd = l:cmd . get(g:, 'hdevtools_options', '') . ' '
   let l:cmd = l:cmd . a:args
   return l:cmd
 endfunction
 
 " Does not include g:hdevtools_options
 function! hdevtools#build_command_bare(command, args)
-  let l:cmd = 'hdevtools'
-  let l:cmd = l:cmd . ' ' . a:command . ' '
+  let l:cmd = g:hdevtools_exe . ' ' . a:command . ' '
   let l:cmd = l:cmd . a:args
   return l:cmd
 endfunction

ftplugin/haskell/hdevtools.vim

@@ -6,7 +6,16 @@ let b:did_ftplugin_hdevtools = 1
 if !exists('s:has_hdevtools')
   let s:has_hdevtools = 0
 
-  if !executable('hdevtools')
+  " For stack support, vim must be started in the directory containing stack.yaml
+  if exists('g:hdevtools_stack') && g:hdevtools_stack && filereadable("stack.yaml")
+    if !executable('stack')
+      call hdevtools#print_error('hdevtools: stack.yaml found, but stack is not executable!')
+      finish
+    endif
+    let g:hdevtools_exe = 'stack exec --silent --no-ghc-package-path --package hdevtools hdevtools --'
+  elseif executable('hdevtools')
+    let g:hdevtools_exe = 'hdevtools'
+  else
     call hdevtools#print_error('hdevtools: hdevtools is not executable!')
     finish
   endif