Add options to facilitate linting only in normal mode (#425)

* [#420] Add options to facilitate linting only in normal mode

ale_lint_on_text_changed:
Allow setting to 'insert' or 'normal' to lint when text is changed only in
insert or normal mode respectively.

ale_lint_on_insert_leave:
This flag can be set to 1 to enable linting when leaving insert mode.

* [#420] Test updated global options

Ale should
- bind to TextChanged events when g:ale_lint_on_text_changed = 1
- bind to TextChanged events when g:ale_lint_on_text_changed = 'always'
- bind to InsertLeave event when g:ale_lint_on_insert_leave = 1

plugin/ale.vim

@@ -69,8 +69,13 @@ let g:ale_linter_aliases = get(g:, 'ale_linter_aliases', {})
 " jobs for linting until enough time has passed after editing is done.
 let g:ale_lint_delay = get(g:, 'ale_lint_delay', 200)
 
-" This flag can be set to 0 to disable linting when text is changed.
-let g:ale_lint_on_text_changed = get(g:, 'ale_lint_on_text_changed', 1)
+" This flag can be set to 'never' to disable linting when text is changed.
+" This flag can also be set to 'insert' or 'normal' to lint when text is
+" changed only in insert or normal mode respectively.
+let g:ale_lint_on_text_changed = get(g:, 'ale_lint_on_text_changed', 'always')
+
+" This flag can be set to 1 to enable linting when leaving insert mode.
+let g:ale_lint_on_insert_leave = get(g:, 'ale_lint_on_insert_leave', 0)
 
 " This flag can be set to 0 to disable linting when the buffer is entered.
 let g:ale_lint_on_enter = get(g:, 'ale_lint_on_enter', 1)
@@ -149,11 +154,17 @@ let g:ale_history_enabled = get(g:, 'ale_history_enabled', 1)
 " A flag for storing the full output of commands in the history.
 let g:ale_history_log_output = get(g:, 'ale_history_log_output', 0)
 
-function! s:ALEInitAuGroups() abort
+function! ALEInitAuGroups() abort
     augroup ALERunOnTextChangedGroup
         autocmd!
-        if g:ale_enabled && g:ale_lint_on_text_changed
-            autocmd TextChanged,TextChangedI * call ale#Queue(g:ale_lint_delay)
+        if g:ale_enabled
+            if g:ale_lint_on_text_changed ==? 'always' || g:ale_lint_on_text_changed == 1
+                autocmd TextChanged,TextChangedI * call ale#Queue(g:ale_lint_delay)
+            elseif g:ale_lint_on_text_changed ==? 'normal'
+                autocmd TextChanged * call ale#Queue(g:ale_lint_delay)
+            elseif g:ale_lint_on_text_changed ==? 'insert'
+                autocmd TextChangedI * call ale#Queue(g:ale_lint_delay)
+            endif
         endif
     augroup END
 
@@ -178,6 +189,13 @@ function! s:ALEInitAuGroups() abort
         endif
     augroup END
 
+    augroup ALERunOnInsertLeave
+        autocmd!
+        if g:ale_enabled && g:ale_lint_on_insert_leave
+            autocmd InsertLeave * call ale#Queue(0, 'lint_file')
+        endif
+    augroup END
+
     augroup ALECursorGroup
         autocmd!
         if g:ale_enabled && g:ale_echo_cursor
@@ -193,6 +211,7 @@ function! s:ALEInitAuGroups() abort
         augroup! ALERunOnTextChangedGroup
         augroup! ALERunOnEnterGroup
         augroup! ALERunOnSaveGroup
+        augroup! ALERunOnInsertLeave
         augroup! ALECursorGroup
     endif
 endfunction
@@ -219,10 +238,10 @@ function! s:ALEToggle() abort
         endif
     endif
 
-    call s:ALEInitAuGroups()
+    call ALEInitAuGroups()
 endfunction
 
-call s:ALEInitAuGroups()
+call ALEInitAuGroups()
 
 " Define commands for moving through warnings and errors.
 command! -bar ALEPrevious :call ale#loclist_jumping#Jump('before', 0)