1 files changed, 91 insertions, 0 deletions
diff --git a/autoload/ale/floating_preview.vim b/autoload/ale/floating_preview.vim
new file mode 100644
index 00000000..e6a75689
--- /dev/null
+++ b/autoload/ale/floating_preview.vim
@@ -0,0 +1,91 @@
+" Author: Jan-Grimo Sobez <jan-grimo.sobez@phys.chem.ethz.ch>
+" Author: Kevin Clark <kevin.clark@gmail.com>
+" Description: Floating preview window for showing whatever information in.
+
+" Precondition: exists('*nvim_open_win')
+
+function! ale#floating_preview#Show(lines, ...) abort
+    if !exists('*nvim_open_win')
+        execute 'echom ''Floating windows not supported in this vim instance.'''
+
+        return
+    endif
+
+    " Remove the close autocmd so it doesn't happen mid update
+    augroup ale_floating_preview_window
+        autocmd!
+    augroup END
+
+    let l:options = get(a:000, 0, {})
+
+    " Only create a new window if we need it
+    if !exists('w:preview') || index(nvim_list_wins(), w:preview['id']) is# -1
+        call s:Create(l:options)
+    else
+        call nvim_buf_set_option(w:preview['buffer'], 'modifiable', v:true)
+    endif
+
+    " Execute commands in window context
+    let l:parent_window = nvim_get_current_win()
+
+    call nvim_set_current_win(w:preview['id'])
+
+    for l:command in get(l:options, 'commands', [])
+        call execute(l:command)
+    endfor
+
+    call nvim_set_current_win(l:parent_window)
+
+    " Return to parent context on move
+    augroup ale_floating_preview_window
+        autocmd!
+
+        if g:ale_close_preview_on_insert
+            autocmd CursorMoved,TabLeave,WinLeave,InsertEnter <buffer> ++once call s:Close()
+        else
+            autocmd CursorMoved,TabLeave,WinLeave <buffer> ++once call s:Close()
+        endif
+    augroup END
+
+    let l:width = max(map(copy(a:lines), 'strdisplaywidth(v:val)'))
+    let l:height = min([len(a:lines), 10])
+    call nvim_win_set_width(w:preview['id'], l:width)
+    call nvim_win_set_height(w:preview['id'], l:height)
+
+    call nvim_buf_set_lines(w:preview['buffer'], 0, -1, v:false, a:lines)
+    call nvim_buf_set_option(w:preview['buffer'], 'modified', v:false)
+    call nvim_buf_set_option(w:preview['buffer'], 'modifiable', v:false)
+endfunction
+
+function! s:Create(options) abort
+    let l:buffer = nvim_create_buf(v:false, v:false)
+    let l:winid = nvim_open_win(l:buffer, v:false, {
+    \ 'relative': 'cursor',
+    \ 'row': 1,
+    \ 'col': 0,
+    \ 'width': 42,
+    \ 'height': 4,
+    \ 'style': 'minimal'
+    \ })
+    call nvim_buf_set_option(l:buffer, 'buftype', 'acwrite')
+    call nvim_buf_set_option(l:buffer, 'bufhidden', 'delete')
+    call nvim_buf_set_option(l:buffer, 'swapfile', v:false)
+    call nvim_buf_set_option(l:buffer, 'filetype', get(a:options, 'filetype', 'ale-preview'))
+
+    let w:preview = {'id': l:winid, 'buffer': l:buffer}
+endfunction
+
+function! s:Close() abort
+    if !exists('w:preview')
+        return
+    endif
+
+    call setbufvar(w:preview['buffer'], '&modified', 0)
+
+    if win_id2win(w:preview['id']) > 0
+        execute win_id2win(w:preview['id']).'wincmd c'
+    endif
+
+    unlet w:preview
+endfunction
+