new NrrwRgn integration

autoload/airline/extensions.vim

@@ -207,6 +207,10 @@ function! airline#extensions#load()
     call airline#extensions#promptline#init(s:ext)
   endif
 
+  if get(g:, 'airline#extensions#nrrwrgn#enabled', 1) && exists(':NR') == 2
+      call airline#extensions#nrrwrgn#init(s:ext)
+  endif
+
   if !get(g:, 'airline#extensions#disable_rtp_load', 0)
     " load all other extensions, which are not part of the default distribution.
     " (autoload/airline/extensions/*.vim outside of our s:script_path).

autoload/airline/extensions/nrrwrgn.vim

@@ -0,0 +1,24 @@
+" MIT License. Copyright (c) 2013-2014 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+if !get(g:, 'loaded_nrrw_rgn', 0)
+  finish
+endif
+
+function! airline#extensions#nrrwrgn#apply(...)
+  if exists(":WidenRegion") == 2
+    let spc = g:airline_symbols.space
+    call a:1.add_section('airline_a', printf('%s[Narrowed%s#%d]', spc, spc, b:nrrw_instn))
+    if exists('*airline#extensions#branch#get_head')
+      call a:1.add_section('airline_b', spc.'%{airline#extensions#branch#get_head()}'.spc)
+    endif
+    let bufname=(get(b:, 'orig_buf', 0) ? bufname(b:orig_buf) : substitute(bufname('%'), '^Nrrwrgn_\zs.*\ze_\d\+$', submatch(0), ''))
+    call a:1.add_section('airline_c', spc.bufname.spc)
+    call a:1.split()
+    return 1
+  endif
+endfunction
+
+function! airline#extensions#nrrwrgn#init(ext)
+  call a:ext.add_statusline_func('airline#extensions#nrrwrgn#apply')
+endfunction

doc/airline.txt

@@ -492,6 +492,11 @@ promptline <https://github.com/edkolev/promptline.vim>
   let airline#extensions#promptline#color_template = 'visual'
   let airline#extensions#promptline#color_template = 'replace'
 <
+-------------------------------------                    *airline-nrrwrgn*
+NrrwRgn <https://github.com/chrisbra/NrrwRgn>
+
+* enable/disable NrrwRgn integration >
+  let g:airline#extensions#nrrwrgn#enabled = 1
 
 ==============================================================================
 ADVANCED CUSTOMIZATION                      *airline-advanced-customization*