From ce83c39bed2d0574bdeeac89f191b2ee1815d650 Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Thu, 4 Jan 2018 20:41:55 +0100
Subject: [PATCH] tabline: allow custom formatter for tabnr_type

closes #1418
---
 .../extensions/tabline/formatters/tabnr.vim        | 14 ++++++++++++++
 autoload/airline/extensions/tabline/tabs.vim       | 13 ++++++-------
 doc/airline.txt                                    |  4 ++++
 3 files changed, 24 insertions(+), 7 deletions(-)
 create mode 100644 autoload/airline/extensions/tabline/formatters/tabnr.vim

diff --git a/autoload/airline/extensions/tabline/formatters/tabnr.vim b/autoload/airline/extensions/tabline/formatters/tabnr.vim
new file mode 100644
index 0000000..87fa7d4
--- /dev/null
+++ b/autoload/airline/extensions/tabline/formatters/tabnr.vim
@@ -0,0 +1,14 @@
+" MIT License. Copyright (c) 2017 C.Brabandt
+" vim: et ts=2 sts=2 sw=2
+
+scriptencoding utf-8
+
+function! airline#extensions#tabline#formatters#tabnr#format(tab_nr_type, nr)
+  if a:tab_nr_type == 0 " nr of splits
+    return (g:airline_symbols.space).'%{len(tabpagebuflist('.a:nr.'))}'
+  elseif a:tab_nr_type == 1 " tab number
+    return (g:airline_symbols.space).a:nr
+  else "== 2 splits and tab number
+    return (g:airline_symbols.space).a:nr.'.%{len(tabpagebuflist('.a:nr.'))}'
+  endif
+endfunction
diff --git a/autoload/airline/extensions/tabline/tabs.vim b/autoload/airline/extensions/tabline/tabs.vim
index 3f3993f..b7a365b 100644
--- a/autoload/airline/extensions/tabline/tabs.vim
+++ b/autoload/airline/extensions/tabline/tabs.vim
@@ -68,13 +68,7 @@ function! airline#extensions#tabline#tabs#get()
     let val = '%('
 
     if get(g:, 'airline#extensions#tabline#show_tab_nr', 1)
-      if tab_nr_type == 0
-        let val .= (g:airline_symbols.space).'%{len(tabpagebuflist('.i.'))}'
-      elseif tab_nr_type == 1
-        let val .= (g:airline_symbols.space).i
-      else "== 2
-        let val .= (g:airline_symbols.space).i.'.%{len(tabpagebuflist('.i.'))}'
-      endif
+      let val .= airline#extensions#tabline#tabs#tabnr_formatter(tab_nr_type, i)
     endif
     call b.add_section(group, val.'%'.i.'T %{airline#extensions#tabline#title('.i.')} %)')
   endfor
@@ -121,3 +115,8 @@ function! airline#extensions#tabline#tabs#map_keys()
   noremap <silent> <Plug>AirlineSelectNextTab :<C-U>exe repeat(':tabn\|', v:count1)<cr>
   let s:airline_tabline_map_key = 1
 endfunction
+
+function! airline#extensions#tabline#tabs#tabnr_formatter(nr, i)
+  let formatter = get(g:, 'airline#extensions#tabline#tabnr_formatter', 'tabnr')
+  return airline#extensions#tabline#formatters#{formatter}#format(a:nr, a:i)
+endfunction
diff --git a/doc/airline.txt b/doc/airline.txt
index e9299e5..fda7453 100644
--- a/doc/airline.txt
+++ b/doc/airline.txt
@@ -685,6 +685,10 @@ with the middle mouse button to delete that buffer.
   let g:airline#extensions#tabline#tab_nr_type = 0 " # of splits (default)
   let g:airline#extensions#tabline#tab_nr_type = 1 " tab number
   let g:airline#extensions#tabline#tab_nr_type = 2 " splits and tab number
+  let g:airline#extensions#tabline#tabnr_formatter = 'tabnr'
+
+  Note: last option can be used to specify a different formatter for
+  displaying the numbers. By default tabline/formatter/tabnr.vim is used
 <
 * enable/disable displaying tab number in tabs mode. >
   let g:airline#extensions#tabline#show_tab_nr = 1