Add spell detection

autoload/airline.vim

@@ -175,6 +175,10 @@ function! airline#check_mode(winnr)
     call add(l:mode, 'crypt')
   endif
 
+  if g:airline_detect_spell && &spell
+    call add(l:mode, 'spell')
+  endif
+
   if &readonly || ! &modifiable
     call add(l:mode, 'readonly')
   endif

autoload/airline/init.vim

@@ -22,6 +22,7 @@ function! airline#init#bootstrap()
   call s:check_defined('g:airline_detect_modified', 1)
   call s:check_defined('g:airline_detect_paste', 1)
   call s:check_defined('g:airline_detect_crypt', 1)
+  call s:check_defined('g:airline_detect_spell', 1)
   call s:check_defined('g:airline_detect_iminsert', 0)
   call s:check_defined('g:airline_inactive_collapse', 1)
   call s:check_defined('g:airline_exclude_filenames', ['DebuggerWatch','DebuggerStack','DebuggerStatus'])
@@ -58,6 +59,7 @@ function! airline#init#bootstrap()
   call s:check_defined('g:airline_symbols', {})
   call extend(g:airline_symbols, {
         \ 'paste': 'PASTE',
+        \ 'spell': 'SPELL',
         \ 'readonly': get(g:, 'airline_powerline_fonts', 0) ? "\ue0a2" : 'RO',
         \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? "\u2739" : '!',
         \ 'linenr': get(g:, 'airline_powerline_fonts', 0) ? "\ue0a1" : ':',
@@ -75,6 +77,7 @@ function! airline#init#bootstrap()
   call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
   call airline#parts#define_function('paste', 'airline#parts#paste')
   call airline#parts#define_function('crypt', 'airline#parts#crypt')
+  call airline#parts#define_function('spell', 'airline#parts#spell')
   call airline#parts#define_function('filetype', 'airline#parts#filetype')
   call airline#parts#define('readonly', {
         \ 'function': 'airline#parts#readonly',
@@ -102,7 +105,7 @@ endfunction
 function! airline#init#sections()
   let spc = g:airline_symbols.space
   if !exists('g:airline_section_a')
-    let g:airline_section_a = airline#section#create_left(['mode', 'crypt', 'paste', 'capslock', 'iminsert'])
+    let g:airline_section_a = airline#section#create_left(['mode', 'crypt', 'paste', 'spell', 'capslock', 'iminsert'])
   endif
   if !exists('g:airline_section_b')
     let g:airline_section_b = airline#section#create(['hunks', 'branch'])

autoload/airline/parts.vim

@@ -62,6 +62,10 @@ function! airline#parts#paste()
   return g:airline_detect_paste && &paste ? g:airline_symbols.paste : ''
 endfunction
 
+function! airline#parts#spell()
+  return g:airline_detect_spell && &spell ? g:airline_symbols.spell : ''
+endfunction
+
 function! airline#parts#iminsert()
   if g:airline_detect_iminsert && &iminsert && exists('b:keymap_name')
     return toupper(b:keymap_name)

doc/airline.txt

@@ -72,6 +72,9 @@ values):
 <
 * enable crypt detection >
   let g:airline_detect_crypt=1
+
+* enable spell detection >
+  let g:airline_detect_spell=1
 <
 * enable iminsert detection >
   let g:airline_detect_iminsert=0
@@ -191,6 +194,7 @@ its contents. >
   let g:airline_symbols.paste = 'ρ'
   let g:airline_symbols.paste = 'Þ'
   let g:airline_symbols.paste = '∥'
+  let g:airline_symbols.spell = 'Ꞩ'
   let g:airline_symbols.notexists = '∄'
   let g:airline_symbols.whitespace = 'Ξ'
 
@@ -223,7 +227,7 @@ section.
 >
   variable names                default contents
   ----------------------------------------------------------------------------
-  let g:airline_section_a       (mode, crypt, paste, iminsert)
+  let g:airline_section_a       (mode, crypt, paste, spell, iminsert)
   let g:airline_section_b       (hunks, branch)
   let g:airline_section_c       (bufferline or filename)
   let g:airline_section_gutter  (readonly, csv)
@@ -771,6 +775,7 @@ Before is a list of parts that are predefined by vim-airline.
 * `iminsert`       displays the current insert method
 * `paste`          displays the paste indicator
 * `crypt`          displays the crypted indicator
+* `spell`          displays the spell indicator
 * `filetype`       displays the file type
 * `readonly`       displays the read only indicator
 * `file`           displays the filename and modified indicator

t/init.vim

@@ -18,9 +18,10 @@ describe 'init sections'
     call s:clear()
   end
 
-  it 'section a should have mode, paste, iminsert'
+  it 'section a should have mode, paste, spell, iminsert'
     Expect g:airline_section_a =~ 'mode'
     Expect g:airline_section_a =~ 'paste'
+    Expect g:airline_section_a =~ 'spell'
     Expect g:airline_section_a =~ 'iminsert'
   end