#1532 - Display hover information on CursorHold

README.md

@@ -231,6 +231,9 @@ ALE supports "hover" information for printing brief information about symbols at
 the cursor taken from Language Server Protocol linters and `tsserver` with the
 `ALEHover` command.
 
+Truncated information will be displayed when the cursor rests on a symbol by
+default, as long as there are no problems on the same line.
+
 The information can be displayed in a `balloon` tooltip in Vim or GVim by
 hovering your mouse over symbols. Mouse hovering is enabled by default in GVim,
 and needs to be configured for Vim 8.1+ in terminals.

autoload/ale/events.vim

@@ -147,6 +147,10 @@ function! ale#events#Init() abort
                 autocmd InsertLeave * if exists('*ale#engine#Cleanup') | call ale#virtualtext#ShowCursorWarning() | endif
             endif
 
+            if g:ale_hover_cursor
+                autocmd CursorHold * if exists('*ale#lsp#Send') | call ale#hover#ShowTruncatedMessageAtCursor() | endif
+            endif
+
             if g:ale_close_preview_on_insert
                 autocmd InsertEnter * if exists('*ale#preview#CloseIfTypeMatches') | call ale#preview#CloseIfTypeMatches('ale-preview') | endif
             endif

autoload/ale/hover.vim

@@ -42,6 +42,8 @@ function! ale#hover#HandleTSServerResponse(conn_id, response) abort
             \&& exists('*balloon_show')
             \&& ale#Var(l:options.buffer, 'set_balloons')
                 call balloon_show(a:response.body.displayString)
+            elseif get(l:options, 'truncated_echo', 0)
+                call ale#cursor#TruncatedEcho(split(a:response.body.displayString, "\n")[0])
             elseif g:ale_hover_to_preview
                 call ale#preview#Show(split(a:response.body.displayString, "\n"), {
                 \   'filetype': 'ale-preview.message',
@@ -156,6 +158,7 @@ function! s:OnReady(line, column, opt, linter, lsp_details) abort
     \   'column': l:column,
     \   'hover_from_balloonexpr': get(a:opt, 'called_from_balloonexpr', 0),
     \   'show_documentation': get(a:opt, 'show_documentation', 0),
+    \   'truncated_echo': get(a:opt, 'truncated_echo', 0),
     \}
 endfunction
 
@@ -189,6 +192,16 @@ function! ale#hover#ShowAtCursor() abort
     call ale#hover#Show(l:buffer, l:pos[1], l:pos[2], {})
 endfunction
 
+function! ale#hover#ShowTruncatedMessageAtCursor() abort
+    let l:buffer = bufnr('')
+    let [l:info, l:loc] = ale#util#FindItemAtCursor(l:buffer)
+
+    if empty(l:loc)
+        let l:pos = getpos('.')
+        call ale#hover#Show(l:buffer, l:pos[1], l:pos[2], {'truncated_echo': 1})
+    endif
+endfunction
+
 " This function implements the :ALEDocumentation command.
 function! ale#hover#ShowDocumentationAtCursor() abort
     let l:buffer = bufnr('')

doc/ale.txt

@@ -516,6 +516,10 @@ at the cursor taken from LSP linters. The following commands are supported:
 
 |ALEHover| - Print information about the symbol at the cursor.
 
+Truncated information will be displayed when the cursor rests on a symbol by
+default, as long as there are no problems on the same line. You can disable
+this behavior by setting |g:ale_hover_cursor| to `0`.
+
 If |g:ale_set_balloons| is set to `1` and your version of Vim supports the
 |balloon_show()| function, then "hover" information also show up when you move
 the mouse over a symbol in a buffer. Diagnostic information will take priority
@@ -1048,9 +1052,27 @@ g:ale_history_log_output                             *g:ale_history_log_output*
   if you want to save on some memory usage.
 
 
+g:ale_hover_cursor                                         *g:ale_hover_cursor*
+
+  Type: |Number|
+  Default: `1`
+
+  If set to `1`, ALE will show truncated information in the echo line about
+  the symbol at the cursor automatically when the |CursorHold| event is fired.
+  The delay before requesting hover information is based on 'updatetime', as
+  with all |CursorHold| events.
+
+  If there's a problem on the line where the cursor is resting, ALE will not
+  show any hover information.
+
+  See |ale-hover| for more information on hover information.
+
+  This setting must be set to `1` before ALE is loaded for this behavior
+  to be enabled. See |ale-lint-settings-on-startup|.
+
+
 g:ale_hover_to_preview                                 *g:ale_hover_to_preview*
                                                        *b:ale_hover_to_preview*
-
   Type: |Number|
   Default: `0`
 

plugin/ale.vim

@@ -121,6 +121,9 @@ let g:ale_cursor_detail = get(g:, 'ale_cursor_detail', 0)
 " This flag can be set to 1 to enable virtual text when the cursor moves.
 let g:ale_virtualtext_cursor = get(g:, 'ale_virtualtext_cursor', 0)
 
+" This flag can be set to 1 to enable LSP hover messages at the cursor.
+let g:ale_hover_cursor = get(g:, 'ale_hover_cursor', 1)
+
 " This flag can be set to 1 to automatically close the preview window upon
 " entering Insert Mode.
 let g:ale_close_preview_on_insert = get(g:, 'ale_close_preview_on_insert', 0)

test/test_autocmd_commands.vader

@@ -49,6 +49,7 @@ Before:
   Save g:ale_lint_on_save
   Save g:ale_lint_on_text_changed
   Save g:ale_pattern_options_enabled
+  Save g:ale_hover_cursor
 
   " Turn everything on by defaul for these tests.
   let g:ale_completion_enabled = 1
@@ -61,6 +62,7 @@ Before:
   let g:ale_lint_on_save = 1
   let g:ale_lint_on_text_changed = 1
   let g:ale_pattern_options_enabled = 1
+  let g:ale_hover_cursor = 1
 
 After:
   delfunction CheckAutocmd
@@ -84,6 +86,7 @@ Execute (All events should be set up when everything is on):
   \   'BufWinEnter * call ale#events#LintOnEnter(str2nr(expand(''<abuf>'')))',
   \   'BufWritePost * call ale#events#SaveEvent(str2nr(expand(''<abuf>'')))',
   \   'CursorHold * if exists(''*ale#engine#Cleanup'') | call ale#cursor#EchoCursorWarningWithDelay() | endif',
+  \   'CursorHold if exists(''*ale#lsp#Send'') | call ale#hover#ShowTruncatedMessageAtCursor() | endif',
   \   'CursorMoved * if exists(''*ale#engine#Cleanup'') | call ale#cursor#EchoCursorWarningWithDelay() | endif',
   \   'FileChangedShellPost * call ale#events#FileChangedEvent(str2nr(expand(''<abuf>'')))',
   \   'FileType * call ale#events#FileTypeEvent( str2nr(expand(''<abuf>'')), expand(''<amatch>''))',
@@ -95,9 +98,9 @@ Execute (All events should be set up when everything is on):
   \ CheckAutocmd('ALEEvents')
 
 Execute (Only the required events should be bound even if various settings are off):
+  let g:ale_enabled = 1
   let g:ale_completion_enabled = 0
   let g:ale_echo_cursor = 0
-  let g:ale_enabled = 0
   let g:ale_fix_on_save = 0
   let g:ale_lint_on_enter = 0
   let g:ale_lint_on_filetype_changed = 0
@@ -105,6 +108,7 @@ Execute (Only the required events should be bound even if various settings are o
   let g:ale_lint_on_save = 0
   let g:ale_lint_on_text_changed = 0
   let g:ale_pattern_options_enabled = 0
+  let g:ale_hover_cursor = 0
 
   AssertEqual
   \ [
@@ -114,6 +118,28 @@ Execute (Only the required events should be bound even if various settings are o
   \ ],
   \ CheckAutocmd('ALEEvents')
 
+Execute (The cursor hoever event should be enabled with g:ale_hover_cursor = 1):
+  let g:ale_enabled = 1
+  let g:ale_completion_enabled = 0
+  let g:ale_echo_cursor = 0
+  let g:ale_fix_on_save = 0
+  let g:ale_lint_on_enter = 0
+  let g:ale_lint_on_filetype_changed = 0
+  let g:ale_lint_on_insert_leave = 0
+  let g:ale_lint_on_save = 0
+  let g:ale_lint_on_text_changed = 0
+  let g:ale_pattern_options_enabled = 0
+  let g:ale_hover_cursor = 1
+
+  AssertEqual
+  \ [
+  \   'BufEnter * call ale#events#ReadOrEnterEvent(str2nr(expand(''<abuf>'')))',
+  \   'BufReadPost * call ale#events#ReadOrEnterEvent(str2nr(expand(''<abuf>'')))',
+  \   'BufWritePost * call ale#events#SaveEvent(str2nr(expand(''<abuf>'')))',
+  \   'CursorHold * if exists(''*ale#lsp#Send'') | call ale#hover#ShowTruncatedMessageAtCursor() | endif',
+  \ ],
+  \ CheckAutocmd('ALEEvents')
+
 Execute (g:ale_lint_on_text_changed = 1 bind both events):
   let g:ale_lint_on_text_changed = 1