Quit guessing the type if the current buffer is modified (#24)

I introduced new variant :GhcModType! and :GhcModTypeInsert! which is
executed even if the current buffer is modified (the previous behavior
of :GhcModType and :GhcModTypeInsert).

after/ftplugin/haskell/ghcmod.vim

@@ -34,8 +34,8 @@ if !exists('g:ghcmod_max_preview_size')
   let g:ghcmod_max_preview_size = 10
 endif
 
-command! -buffer -nargs=0 GhcModType call s:echo(ghcmod#type()[1])
-command! -buffer -nargs=0 GhcModTypeInsert call ghcmod#type_insert()
+command! -buffer -nargs=0 -bang GhcModType call s:type(<bang>0)
+command! -buffer -nargs=0 -bang GhcModTypeInsert call ghcmod#type_insert(<bang>0)
 command! -buffer -nargs=? GhcModInfo call s:echo(s:info(<q-args>))
 command! -buffer -nargs=0 GhcModTypeClear call ghcmod#type_clear()
 command! -buffer -nargs=? GhcModInfoPreview call ghcmod#preview(s:info(<q-args>), g:ghcmod_max_preview_size)
@@ -69,6 +69,13 @@ function! s:echo(msg)
   endif
 endfunction
 
+function! s:type(force)
+  let l:type = ghcmod#type(a:force)[1]
+  if !empty(l:type)
+    echo l:type
+  endif
+endfunction
+
 function! s:make(type)
   let l:qflist = ghcmod#make(a:type)
   call setqflist(l:qflist)

autoload/ghcmod.vim

@@ -78,9 +78,15 @@ function! ghcmod#info(fexp)"{{{
   return l:output
 endfunction"}}}
 
-function! ghcmod#type()"{{{
+function! ghcmod#type(force)"{{{
   if &l:modified
-    call ghcmod#print_warning('ghcmod#type: the buffer has been modified but not written')
+    let l:msg = 'ghcmod#type: the buffer has been modified but not written'
+    if a:force
+      call ghcmod#print_warning(l:msg)
+    else
+      call ghcmod#print_error(l:msg)
+      return ['', '']
+    endif
   endif
   let l:line = line('.')
   let l:col = col('.')
@@ -506,7 +512,7 @@ function! ghcmod#version()"{{{
   return [0, 3, 0]
 endfunction"}}}
 
-function! ghcmod#type_insert() "{{{
+function! ghcmod#type_insert(force) "{{{
   let fexp = ghcmod#getHaskellIdentifier()
   if !exists('fexp') || fexp  == ''
     call ghcmod#print_error('Failed to determine identifier under cursor.')
@@ -516,7 +522,7 @@ function! ghcmod#type_insert() "{{{
   if exists("b:ghcmod_type")
     unlet b:ghcmod_type " Make sure we aren't doing some weird persistence tricks
   endif
-  let [locsym, type] = ghcmod#type()
+  let [locsym, type] = ghcmod#type(a:force)
   call ghcmod#clear_highlight()
   if type == "" " Everything failed so let's just abort
     return

doc/ghcmod.txt

@@ -48,6 +48,21 @@ If you'd like to give GHC options, set |g:ghcmod_ghc_options|.
 	Sub-expressions are highlighted as |hl-Search| by default. You can
 	customize it by setting |g:ghcmod_type_highlight|.
 
+	If the current buffer is modified, this command is disabled.
+
+:GhcModType!                                                    *:GhcModType!*
+	Same as |:GhcModType|, but this command is executed even if the
+	current buffer is modified.
+
+:GhcModTypeInsert                                          *:GhcModTypeInsert*
+	Insert a type signature under the cursor.
+
+	If the current buffer is modified, this command is disabled.
+
+:GhcModTypeInsert!                                        *:GhcModTypeInsert!*
+	Same as |:GhcModTypeInsert|, but this command is executed even if the
+	current buffer is modified.
+
 :GhcModInfo                                                      *:GhcModInfo*
 	Information about the identifier under the cursor is echoed.