From e10b690cdfd3f29ca3db0e76baeced7872d9b5be Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Wed, 28 Aug 2013 23:29:35 +0000
Subject: [PATCH 01/20] convert mode/paste/iminsert parts to function names.

---
 autoload/airline/parts.vim | 22 ++++++++++++++++++++--
 autoload/airline/util.vim  | 18 ++++++++++++++++++
 plugin/airline.vim         | 20 ++++++++++----------
 3 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index 0c7ece9..917a469 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -1,13 +1,31 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
+function! airline#parts#append(name)
+  let val = function(a:name)()
+  return empty(val) ? '' : '  '.g:airline_left_alt_sep.' '.val
+endfunction
+
+function! airline#parts#prepend(name)
+  let val = function(a:name)()
+  return empty(val) ? '' : val.' '.g:airline_right_alt_sep
+endfunction
+
+function! airline#parts#empty()
+  return ''
+endfunction
+
+function! airline#parts#mode()
+  return get(w:, 'airline_current_mode', '')
+endfunction
+
 function! airline#parts#paste()
-  return g:airline_detect_paste && &paste ? '  '.g:airline_symbols.paste : ''
+  return g:airline_detect_paste && &paste ? g:airline_symbols.paste : ''
 endfunction
 
 function! airline#parts#iminsert()
   if g:airline_detect_iminsert && &iminsert && exists('b:keymap_name')
-    return '  '.g:airline_left_alt_sep.' '.toupper(b:keymap_name)
+    return toupper(b:keymap_name)
   endif
   return ''
 endfunction
diff --git a/autoload/airline/util.vim b/autoload/airline/util.vim
index 3581698..e556024 100644
--- a/autoload/airline/util.vim
+++ b/autoload/airline/util.vim
@@ -1,6 +1,24 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
+function! s:get_val(part)
+  let val = g:airline_parts[a:part]
+  if match(val, '%') > -1
+    return val
+  else
+    return '%{function("'.val.'")()}'
+  endif
+endfunction
+
+function! airline#util#define_section(key, parts)
+  if !exists('g:airline_section_{a:key}') && len(a:parts) > 0
+    let g:airline_section_{a:key} = s:get_val(a:parts[0])
+    for i in range(1, len(a:parts) - 1)
+      let g:airline_section_{a:key} .= s:get_val(a:parts[i])
+    endfor
+  endif
+endfunction
+
 if v:version >= 704
   function! airline#util#getwinvar(winnr, key, def)
     return getwinvar(a:winnr, a:key, a:def)
diff --git a/plugin/airline.vim b/plugin/airline.vim
index 0547d4d..341a8a7 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -34,7 +34,7 @@ function! s:init()
 
     call s:check_defined('g:airline_symbols', {})
     call extend(g:airline_symbols, {
-          \ 'paste': get(g:, 'airline_paste_symbol', g:airline_left_alt_sep.' PASTE'),
+          \ 'paste': get(g:, 'airline_paste_symbol', 'PASTE'),
           \ 'readonly': get(g:, 'airline_readonly_symbol', get(g:, 'airline_powerline_fonts', 0) ? '' : 'RO'),
           \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? '✹' : '!',
           \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
@@ -43,17 +43,17 @@ function! s:init()
 
     call s:check_defined('g:airline_parts', {})
     call extend(g:airline_parts, {
-          \ 'mode': '%{get(w:,"airline_current_mode","")}',
-          \ 'iminsert': '%{airline#parts#iminsert()}',
-          \ 'paste': '%{airline#parts#paste()}',
+          \ 'mode': 'airline#parts#mode',
+          \ 'iminsert': 'airline#parts#iminsert',
+          \ 'paste': 'airline#parts#paste',
           \ 'readonly': '%#airline_file#%{airline#parts#readonly()}',
           \ 'ffenc': '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}',
           \ 'file': '%f%m',
-          \ 'hunks': '',
-          \ 'branch': '',
-          \ 'tagbar': '',
-          \ 'syntastic': '',
-          \ 'whitespace': '',
+          \ 'hunks': 'airline#parts#empty',
+          \ 'branch': 'airline#parts#empty',
+          \ 'tagbar': 'airline#parts#empty',
+          \ 'syntastic': 'airline#parts#empty',
+          \ 'whitespace': 'airline#parts#empty',
           \ }, 'keep')
 
     call s:check_defined('g:airline_mode_map', {})
@@ -80,7 +80,7 @@ function! s:init()
           \ }, 'keep')
 
     call airline#extensions#load()
-    call s:check_defined('g:airline_section_a', (g:airline_parts.mode).(g:airline_parts.paste).(g:airline_parts.iminsert))
+    call airline#util#define_section('a', ['mode', 'paste', 'iminsert'])
     call s:check_defined('g:airline_section_b', (g:airline_parts.hunks).(g:airline_parts.branch))
     call s:check_defined('g:airline_section_c', '%<'.(g:airline_parts.file))
     call s:check_defined('g:airline_section_gutter', ' '.(g:airline_parts.readonly).'%=')

From bdd758dd3885fcc5a5bf5eed49dc1a196d2a54ac Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Thu, 29 Aug 2013 00:15:07 +0000
Subject: [PATCH 02/20] convert branch/hunks/bufferline to function names.

---
 autoload/airline/extensions/branch.vim |  2 +-
 autoload/airline/extensions/hunks.vim  |  2 +-
 autoload/airline/util.vim              | 13 ++++++++-----
 plugin/airline.vim                     |  4 ++--
 4 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/autoload/airline/extensions/branch.vim b/autoload/airline/extensions/branch.vim
index a746ea6..14dc8af 100644
--- a/autoload/airline/extensions/branch.vim
+++ b/autoload/airline/extensions/branch.vim
@@ -31,6 +31,6 @@ function! airline#extensions#branch#get_head()
 endfunction
 
 function! airline#extensions#branch#init(ext)
-  let g:airline_parts.branch = '%{airline#extensions#branch#get_head()}'
+  let g:airline_parts.branch = 'airline#extensions#branch#get_head'
 endfunction
 
diff --git a/autoload/airline/extensions/hunks.vim b/autoload/airline/extensions/hunks.vim
index 66403b1..0c5ee50 100644
--- a/autoload/airline/extensions/hunks.vim
+++ b/autoload/airline/extensions/hunks.vim
@@ -54,6 +54,6 @@ function! airline#extensions#hunks#get_hunks()
 endfunction
 
 function! airline#extensions#hunks#init(ext)
-  let g:airline_parts.hunks = '%{airline#extensions#hunks#get_hunks()}'
+  let g:airline_parts.hunks = 'airline#extensions#hunks#get_hunks'
 endfunction
 
diff --git a/autoload/airline/util.vim b/autoload/airline/util.vim
index e556024..624e5e8 100644
--- a/autoload/airline/util.vim
+++ b/autoload/airline/util.vim
@@ -2,12 +2,15 @@
 " vim: et ts=2 sts=2 sw=2
 
 function! s:get_val(part)
-  let val = g:airline_parts[a:part]
-  if match(val, '%') > -1
-    return val
-  else
-    return '%{function("'.val.'")()}'
+  if has_key(g:airline_parts, a:part)
+    let val = g:airline_parts[a:part]
+    if match(val, '%\| ') > -1
+      return val
+    else
+      return '%{'.val.'()}'
+    endif
   endif
+  return a:part
 endfunction
 
 function! airline#util#define_section(key, parts)
diff --git a/plugin/airline.vim b/plugin/airline.vim
index 341a8a7..e5b812b 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -81,8 +81,8 @@ function! s:init()
 
     call airline#extensions#load()
     call airline#util#define_section('a', ['mode', 'paste', 'iminsert'])
-    call s:check_defined('g:airline_section_b', (g:airline_parts.hunks).(g:airline_parts.branch))
-    call s:check_defined('g:airline_section_c', '%<'.(g:airline_parts.file))
+    call airline#util#define_section('b', ['hunks', 'branch'])
+    call airline#util#define_section('c', ['%<', 'file'])
     call s:check_defined('g:airline_section_gutter', ' '.(g:airline_parts.readonly).'%=')
     call s:check_defined('g:airline_section_x', (g:airline_parts.tagbar).'%{&filetype}')
     call s:check_defined('g:airline_section_y', g:airline_parts.ffenc)

From e13a4c8b1a0f46e6c51c192f462af141246f781e Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Thu, 29 Aug 2013 00:36:07 +0000
Subject: [PATCH 03/20] convert the rest to use define section.

---
 autoload/airline/extensions/tagbar.vim | 10 ++++++++--
 plugin/airline.vim                     | 10 +++++-----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/autoload/airline/extensions/tagbar.vim b/autoload/airline/extensions/tagbar.vim
index bf7efee..4b51787 100644
--- a/autoload/airline/extensions/tagbar.vim
+++ b/autoload/airline/extensions/tagbar.vim
@@ -16,11 +16,17 @@ function! airline#extensions#tagbar#inactive_apply(...)
   endif
 endfunction
 
+function! airline#extensions#tagbar#currenttag()
+  if get(w:, 'airline_active', 0)
+    return tagbar#currenttag('%s', '')
+  endif
+  return ''
+endfunction
+
 function! airline#extensions#tagbar#init(ext)
   call a:ext.add_inactive_statusline_func('airline#extensions#tagbar#inactive_apply')
   let g:tagbar_status_func = 'airline#extensions#tagbar#get_status'
 
-  let g:airline_parts.tagbar = '%(%{get(w:,"airline_active",0) ? tagbar#currenttag("%s","") : ""} '
-        \ .g:airline_right_alt_sep.' %)'
+  let g:airline_parts.tagbar = 'airline#extensions#tagbar#currenttag'
 endfunction
 
diff --git a/plugin/airline.vim b/plugin/airline.vim
index e5b812b..179446f 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -83,11 +83,11 @@ function! s:init()
     call airline#util#define_section('a', ['mode', 'paste', 'iminsert'])
     call airline#util#define_section('b', ['hunks', 'branch'])
     call airline#util#define_section('c', ['%<', 'file'])
-    call s:check_defined('g:airline_section_gutter', ' '.(g:airline_parts.readonly).'%=')
-    call s:check_defined('g:airline_section_x', (g:airline_parts.tagbar).'%{&filetype}')
-    call s:check_defined('g:airline_section_y', g:airline_parts.ffenc)
-    call s:check_defined('g:airline_section_z', '%3p%% %{g:airline_symbols.linenr} %3l:%3c ')
-    call s:check_defined('g:airline_section_warning', (g:airline_parts.syntastic).(g:airline_parts.whitespace))
+    call airline#util#define_section('gutter', ['readonly', '%='])
+    call airline#util#define_section('x', ['tagbar', '%{&filetype}'])
+    call airline#util#define_section('y', ['ffenc'])
+    call airline#util#define_section('z', ['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    call airline#util#define_section('warning', ['syntastic', 'whitespace'])
 
     let s:airline_theme_defined = exists('g:airline_theme')
     if s:airline_theme_defined || !airline#switch_matching_theme()

From a927bf947592fe865c668887355ab9938545407a Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Thu, 29 Aug 2013 00:57:58 +0000
Subject: [PATCH 04/20] automatic separators.

---
 autoload/airline/parts.vim |  2 +-
 autoload/airline/util.vim  | 22 ++++++++++++++++++----
 plugin/airline.vim         | 16 ++++++++--------
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index 917a469..63fe741 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -8,7 +8,7 @@ endfunction
 
 function! airline#parts#prepend(name)
   let val = function(a:name)()
-  return empty(val) ? '' : val.' '.g:airline_right_alt_sep
+  return empty(val) ? '' : val.' '.g:airline_right_alt_sep.' '
 endfunction
 
 function! airline#parts#empty()
diff --git a/autoload/airline/util.vim b/autoload/airline/util.vim
index 624e5e8..3de33c3 100644
--- a/autoload/airline/util.vim
+++ b/autoload/airline/util.vim
@@ -1,11 +1,15 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-function! s:get_val(part)
+function! s:get_val(part, append)
   if has_key(g:airline_parts, a:part)
     let val = g:airline_parts[a:part]
     if match(val, '%\| ') > -1
       return val
+    elseif a:append > 0
+      return '%{airline#parts#append("'.val.'")}'
+    elseif a:append < 0
+      return '%{airline#parts#prepend("'.val.'")}'
     else
       return '%{'.val.'()}'
     endif
@@ -13,15 +17,25 @@ function! s:get_val(part)
   return a:part
 endfunction
 
-function! airline#util#define_section(key, parts)
+function! airline#util#define_left_section(key, parts)
   if !exists('g:airline_section_{a:key}') && len(a:parts) > 0
-    let g:airline_section_{a:key} = s:get_val(a:parts[0])
+    let g:airline_section_{a:key} = s:get_val(a:parts[0], 0)
     for i in range(1, len(a:parts) - 1)
-      let g:airline_section_{a:key} .= s:get_val(a:parts[i])
+      let g:airline_section_{a:key} .= s:get_val(a:parts[i], 1)
     endfor
   endif
 endfunction
 
+function! airline#util#define_right_section(key, parts)
+  if !exists('g:airline_section_{a:key}') && len(a:parts) > 0
+    let g:airline_section_{a:key} = ''
+    for i in range(0, len(a:parts) - 2)
+      let g:airline_section_{a:key} .= s:get_val(a:parts[i], -1)
+    endfor
+    let g:airline_section_{a:key} .= s:get_val(a:parts[-1], 0)
+  endif
+endfunction
+
 if v:version >= 704
   function! airline#util#getwinvar(winnr, key, def)
     return getwinvar(a:winnr, a:key, a:def)
diff --git a/plugin/airline.vim b/plugin/airline.vim
index 179446f..7e64569 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -80,14 +80,14 @@ function! s:init()
           \ }, 'keep')
 
     call airline#extensions#load()
-    call airline#util#define_section('a', ['mode', 'paste', 'iminsert'])
-    call airline#util#define_section('b', ['hunks', 'branch'])
-    call airline#util#define_section('c', ['%<', 'file'])
-    call airline#util#define_section('gutter', ['readonly', '%='])
-    call airline#util#define_section('x', ['tagbar', '%{&filetype}'])
-    call airline#util#define_section('y', ['ffenc'])
-    call airline#util#define_section('z', ['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
-    call airline#util#define_section('warning', ['syntastic', 'whitespace'])
+    call airline#util#define_left_section('a', ['mode', 'paste', 'iminsert'])
+    call airline#util#define_left_section('b', ['hunks', 'branch'])
+    call airline#util#define_left_section('c', ['%<', 'file'])
+    call airline#util#define_left_section('gutter', ['readonly', '%='])
+    call airline#util#define_right_section('x', ['tagbar', '%{&filetype}'])
+    call airline#util#define_right_section('y', ['ffenc'])
+    call airline#util#define_right_section('z', ['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    call airline#util#define_right_section('warning', ['syntastic', 'whitespace'])
 
     let s:airline_theme_defined = exists('g:airline_theme')
     if s:airline_theme_defined || !airline#switch_matching_theme()

From fa517238c771c9749b1e87870ced8b61fb8bb169 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:51:10 +0000
Subject: [PATCH 05/20] introduce parts metadata.

---
 autoload/airline/extensions/branch.vim     |  2 +-
 autoload/airline/extensions/bufferline.vim |  3 +-
 autoload/airline/extensions/hunks.vim      |  2 +-
 autoload/airline/parts.vim                 | 25 +++++++++++----
 autoload/airline/util.vim                  | 35 +++-----------------
 plugin/airline.vim                         | 37 +++++++++++++---------
 6 files changed, 49 insertions(+), 55 deletions(-)

diff --git a/autoload/airline/extensions/branch.vim b/autoload/airline/extensions/branch.vim
index 14dc8af..446c89d 100644
--- a/autoload/airline/extensions/branch.vim
+++ b/autoload/airline/extensions/branch.vim
@@ -31,6 +31,6 @@ function! airline#extensions#branch#get_head()
 endfunction
 
 function! airline#extensions#branch#init(ext)
-  let g:airline_parts.branch = 'airline#extensions#branch#get_head'
+  call airline#parts#define_function('branch', 'airline#extensions#branch#get_head')
 endfunction
 
diff --git a/autoload/airline/extensions/bufferline.vim b/autoload/airline/extensions/bufferline.vim
index 4a6e014..cc13ec0 100644
--- a/autoload/airline/extensions/bufferline.vim
+++ b/autoload/airline/extensions/bufferline.vim
@@ -14,5 +14,6 @@ function! airline#extensions#bufferline#init(ext)
     let g:bufferline_separator = ' '
   endif
 
-  let g:airline_parts.file = '%{bufferline#refresh_status()}'.bufferline#get_status_string()
+  call airline#parts#define_raw('file', '%{bufferline#refresh_status()}'.bufferline#get_status_string())
 endfunction
+
diff --git a/autoload/airline/extensions/hunks.vim b/autoload/airline/extensions/hunks.vim
index 0c5ee50..803dfaf 100644
--- a/autoload/airline/extensions/hunks.vim
+++ b/autoload/airline/extensions/hunks.vim
@@ -54,6 +54,6 @@ function! airline#extensions#hunks#get_hunks()
 endfunction
 
 function! airline#extensions#hunks#init(ext)
-  let g:airline_parts.hunks = 'airline#extensions#hunks#get_hunks'
+  call airline#parts#define_function('hunks', 'airline#extensions#hunks#get_hunks')
 endfunction
 
diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index 63fe741..42ab21e 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -1,14 +1,27 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-function! airline#parts#append(name)
-  let val = function(a:name)()
-  return empty(val) ? '' : '  '.g:airline_left_alt_sep.' '.val
+let s:parts = {}
+
+function! airline#parts#define(key, config)
+  let s:parts[a:key] = get(s:parts, a:key, {})
+  call extend(s:parts[a:key], a:config)
 endfunction
 
-function! airline#parts#prepend(name)
-  let val = function(a:name)()
-  return empty(val) ? '' : val.' '.g:airline_right_alt_sep.' '
+function! airline#parts#define_function(key, name)
+  call airline#parts#define(a:key, { 'function': a:name })
+endfunction
+
+function! airline#parts#define_text(key, text)
+  call airline#parts#define(a:key, { 'text': a:text })
+endfunction
+
+function! airline#parts#define_raw(key, raw)
+  call airline#parts#define(a:key, { 'raw': a:raw })
+endfunction
+
+function! airline#parts#get(key)
+  return get(s:parts, a:key, {})
 endfunction
 
 function! airline#parts#empty()
diff --git a/autoload/airline/util.vim b/autoload/airline/util.vim
index 3de33c3..e7b27f8 100644
--- a/autoload/airline/util.vim
+++ b/autoload/airline/util.vim
@@ -1,39 +1,12 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-function! s:get_val(part, append)
-  if has_key(g:airline_parts, a:part)
-    let val = g:airline_parts[a:part]
-    if match(val, '%\| ') > -1
-      return val
-    elseif a:append > 0
-      return '%{airline#parts#append("'.val.'")}'
-    elseif a:append < 0
-      return '%{airline#parts#prepend("'.val.'")}'
-    else
-      return '%{'.val.'()}'
-    endif
-  endif
-  return a:part
+function! airline#util#append(text)
+  return empty(a:text) ? '' : '  '.g:airline_left_alt_sep.' '.a:text
 endfunction
 
-function! airline#util#define_left_section(key, parts)
-  if !exists('g:airline_section_{a:key}') && len(a:parts) > 0
-    let g:airline_section_{a:key} = s:get_val(a:parts[0], 0)
-    for i in range(1, len(a:parts) - 1)
-      let g:airline_section_{a:key} .= s:get_val(a:parts[i], 1)
-    endfor
-  endif
-endfunction
-
-function! airline#util#define_right_section(key, parts)
-  if !exists('g:airline_section_{a:key}') && len(a:parts) > 0
-    let g:airline_section_{a:key} = ''
-    for i in range(0, len(a:parts) - 2)
-      let g:airline_section_{a:key} .= s:get_val(a:parts[i], -1)
-    endfor
-    let g:airline_section_{a:key} .= s:get_val(a:parts[-1], 0)
-  endif
+function! airline#util#prepend(text)
+  return empty(a:text) ? '' : a:text.' '.g:airline_right_alt_sep.' '
 endfunction
 
 if v:version >= 704
diff --git a/plugin/airline.vim b/plugin/airline.vim
index 7e64569..b54ae3c 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -41,16 +41,18 @@ function! s:init()
           \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
           \ }, 'keep')
 
+    call airline#parts#define_function('mode', 'airline#parts#mode')
+    call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
+    call airline#parts#define_function('paste', 'airline#parts#paste')
+    call airline#parts#define('readonly', {
+          \ 'function': 'airline#parts#readonly',
+          \ 'highlight': 'airline_file',
+          \ })
+    call airline#parts#define_raw('file', '%f%m')
+
     call s:check_defined('g:airline_parts', {})
     call extend(g:airline_parts, {
-          \ 'mode': 'airline#parts#mode',
-          \ 'iminsert': 'airline#parts#iminsert',
-          \ 'paste': 'airline#parts#paste',
-          \ 'readonly': '%#airline_file#%{airline#parts#readonly()}',
           \ 'ffenc': '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}',
-          \ 'file': '%f%m',
-          \ 'hunks': 'airline#parts#empty',
-          \ 'branch': 'airline#parts#empty',
           \ 'tagbar': 'airline#parts#empty',
           \ 'syntastic': 'airline#parts#empty',
           \ 'whitespace': 'airline#parts#empty',
@@ -80,14 +82,19 @@ function! s:init()
           \ }, 'keep')
 
     call airline#extensions#load()
-    call airline#util#define_left_section('a', ['mode', 'paste', 'iminsert'])
-    call airline#util#define_left_section('b', ['hunks', 'branch'])
-    call airline#util#define_left_section('c', ['%<', 'file'])
-    call airline#util#define_left_section('gutter', ['readonly', '%='])
-    call airline#util#define_right_section('x', ['tagbar', '%{&filetype}'])
-    call airline#util#define_right_section('y', ['ffenc'])
-    call airline#util#define_right_section('z', ['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
-    call airline#util#define_right_section('warning', ['syntastic', 'whitespace'])
+
+    if !exists('g:airline_section_a')
+      let g:airline_section_a = airline#section#create_left(['mode', 'paste', 'iminsert'])
+    endif
+    if !exists('g:airline_section_b')
+      let g:airline_section_b = airline#section#create(['hunks', 'branch'])
+    endif
+    let g:airline_section_c = airline#section#create(['%<', 'file'])
+    let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
+    let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
+    let g:airline_section_y = airline#section#create(['ffenc'])
+    let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
 
     let s:airline_theme_defined = exists('g:airline_theme')
     if s:airline_theme_defined || !airline#switch_matching_theme()

From 93eb0389b91c610a8e371d7548f6d4b70fe72ff7 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:56:12 +0000
Subject: [PATCH 06/20] move init code into new file, add section.

---
 autoload/airline/init.vim    | 87 ++++++++++++++++++++++++++++++++++++
 autoload/airline/section.vim | 47 +++++++++++++++++++
 plugin/airline.vim           | 82 +--------------------------------
 3 files changed, 135 insertions(+), 81 deletions(-)
 create mode 100644 autoload/airline/init.vim
 create mode 100644 autoload/airline/section.vim

diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
new file mode 100644
index 0000000..cb53f5e
--- /dev/null
+++ b/autoload/airline/init.vim
@@ -0,0 +1,87 @@
+" MIT License. Copyright (c) 2013 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+function! s:check_defined(variable, default)
+  if !exists(a:variable)
+    let {a:variable} = a:default
+  endif
+endfunction
+
+function! airline#init#bootstrap()
+  call s:check_defined('g:airline_left_sep', get(g:, 'airline_powerline_fonts', 0)?"":">")
+  call s:check_defined('g:airline_left_alt_sep', get(g:, 'airline_powerline_fonts', 0)?"":">")
+  call s:check_defined('g:airline_right_sep', get(g:, 'airline_powerline_fonts', 0)?"":"<")
+  call s:check_defined('g:airline_right_alt_sep', get(g:, 'airline_powerline_fonts', 0)?"":"<")
+  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_iminsert', 0)
+  call s:check_defined('g:airline_inactive_collapse', 1)
+  call s:check_defined('g:airline_exclude_filenames', ['DebuggerWatch','DebuggerStack','DebuggerStatus'])
+  call s:check_defined('g:airline_exclude_filetypes', [])
+  call s:check_defined('g:airline_exclude_preview', 0)
+
+  call s:check_defined('g:airline_symbols', {})
+  call extend(g:airline_symbols, {
+        \ 'paste': get(g:, 'airline_paste_symbol', 'PASTE'),
+        \ 'readonly': get(g:, 'airline_readonly_symbol', get(g:, 'airline_powerline_fonts', 0) ? '' : 'RO'),
+        \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? '✹' : '!',
+        \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
+        \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
+        \ }, 'keep')
+
+  call airline#parts#define_function('mode', 'airline#parts#mode')
+  call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
+  call airline#parts#define_function('paste', 'airline#parts#paste')
+  call airline#parts#define('readonly', {
+        \ 'function': 'airline#parts#readonly',
+        \ 'highlight': 'airline_file',
+        \ })
+  call airline#parts#define_raw('file', '%f%m')
+
+  call s:check_defined('g:airline_parts', {})
+  call extend(g:airline_parts, {
+        \ 'ffenc': '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}',
+        \ 'tagbar': 'airline#parts#empty',
+        \ 'syntastic': 'airline#parts#empty',
+        \ 'whitespace': 'airline#parts#empty',
+        \ }, 'keep')
+
+  call s:check_defined('g:airline_mode_map', {})
+  call extend(g:airline_mode_map, {
+        \ '__' : '------',
+        \ 'n'  : 'NORMAL',
+        \ 'i'  : 'INSERT',
+        \ 'R'  : 'REPLACE',
+        \ 'v'  : 'VISUAL',
+        \ 'V'  : 'V-LINE',
+        \ 'c'  : 'COMMAND',
+        \ '' : 'V-BLOCK',
+        \ 's'  : 'SELECT',
+        \ 'S'  : 'S-LINE',
+        \ '' : 'S-BLOCK',
+        \ }, 'keep')
+
+  call s:check_defined('g:airline_theme_map', {})
+  call extend(g:airline_theme_map, {
+        \ 'Tomorrow.*': 'tomorrow',
+        \ 'mo[l|n]okai': 'molokai',
+        \ 'wombat.*': 'wombat',
+        \ '.*solarized.*': 'solarized',
+        \ }, 'keep')
+
+  call airline#extensions#load()
+
+  if !exists('g:airline_section_a')
+    let g:airline_section_a = airline#section#create_left(['mode', 'paste', 'iminsert'])
+  endif
+  if !exists('g:airline_section_b')
+    let g:airline_section_b = airline#section#create(['hunks', 'branch'])
+  endif
+  let g:airline_section_c = airline#section#create(['%<', 'file'])
+  let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
+  let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
+  let g:airline_section_y = airline#section#create(['ffenc'])
+  let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+  let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
+endfunction
+
diff --git a/autoload/airline/section.vim b/autoload/airline/section.vim
new file mode 100644
index 0000000..788b443
--- /dev/null
+++ b/autoload/airline/section.vim
@@ -0,0 +1,47 @@
+" MIT License. Copyright (c) 2013 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+function! s:get_val(key, append)
+  let val = ''
+  let part = airline#parts#get(a:key)
+  if exists('part.function')
+    let func = (part.function).'()'
+  elseif exists('part.text')
+    let func = '"'.(part.text).'"'
+  elseif exists('part.raw')
+    return part.raw
+  else
+    return a:key
+  endif
+
+  if a:append > 0
+    let val .= '%{airline#util#append('.func.')}'
+  elseif a:append < 0
+    return '%{airline#util#prepend('.func.')}'
+  else
+    return '%{'.func.'}'
+  endif
+  return val
+endfunction
+
+function! airline#section#create(parts)
+  return join(map(a:parts, 's:get_val(v:val, 0)'), '')
+endfunction
+
+function! airline#section#create_left(parts)
+  let _ = s:get_val(a:parts[0], 0)
+  for i in range(1, len(a:parts) - 1)
+    let _ .= s:get_val(a:parts[i], 1)
+  endfor
+  return _
+endfunction
+
+function! airline#section#create_right(parts)
+  let _ = ''
+  for i in range(0, len(a:parts) - 2)
+    let _ .= s:get_val(a:parts[i], -1)
+  endfor
+  let _ .= s:get_val(a:parts[-1], 0)
+  return _
+endfunction
+
diff --git a/plugin/airline.vim b/plugin/airline.vim
index b54ae3c..f1164da 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -8,93 +8,13 @@ let g:loaded_airline = 1
 
 " autocmd VimEnter * call airline#deprecation#check()
 
-function! s:check_defined(variable, default)
-  if !exists(a:variable)
-    let {a:variable} = a:default
-  endif
-endfunction
-
 let s:airline_initialized = 0
 let s:airline_theme_defined = 0
 function! s:init()
   if !s:airline_initialized
     let s:airline_initialized = 1
 
-    call s:check_defined('g:airline_left_sep', get(g:, 'airline_powerline_fonts', 0)?"":">")
-    call s:check_defined('g:airline_left_alt_sep', get(g:, 'airline_powerline_fonts', 0)?"":">")
-    call s:check_defined('g:airline_right_sep', get(g:, 'airline_powerline_fonts', 0)?"":"<")
-    call s:check_defined('g:airline_right_alt_sep', get(g:, 'airline_powerline_fonts', 0)?"":"<")
-    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_iminsert', 0)
-    call s:check_defined('g:airline_inactive_collapse', 1)
-    call s:check_defined('g:airline_exclude_filenames', ['DebuggerWatch','DebuggerStack','DebuggerStatus'])
-    call s:check_defined('g:airline_exclude_filetypes', [])
-    call s:check_defined('g:airline_exclude_preview', 0)
-
-    call s:check_defined('g:airline_symbols', {})
-    call extend(g:airline_symbols, {
-          \ 'paste': get(g:, 'airline_paste_symbol', 'PASTE'),
-          \ 'readonly': get(g:, 'airline_readonly_symbol', get(g:, 'airline_powerline_fonts', 0) ? '' : 'RO'),
-          \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? '✹' : '!',
-          \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
-          \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
-          \ }, 'keep')
-
-    call airline#parts#define_function('mode', 'airline#parts#mode')
-    call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
-    call airline#parts#define_function('paste', 'airline#parts#paste')
-    call airline#parts#define('readonly', {
-          \ 'function': 'airline#parts#readonly',
-          \ 'highlight': 'airline_file',
-          \ })
-    call airline#parts#define_raw('file', '%f%m')
-
-    call s:check_defined('g:airline_parts', {})
-    call extend(g:airline_parts, {
-          \ 'ffenc': '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}',
-          \ 'tagbar': 'airline#parts#empty',
-          \ 'syntastic': 'airline#parts#empty',
-          \ 'whitespace': 'airline#parts#empty',
-          \ }, 'keep')
-
-    call s:check_defined('g:airline_mode_map', {})
-    call extend(g:airline_mode_map, {
-          \ '__' : '------',
-          \ 'n'  : 'NORMAL',
-          \ 'i'  : 'INSERT',
-          \ 'R'  : 'REPLACE',
-          \ 'v'  : 'VISUAL',
-          \ 'V'  : 'V-LINE',
-          \ 'c'  : 'COMMAND',
-          \ '' : 'V-BLOCK',
-          \ 's'  : 'SELECT',
-          \ 'S'  : 'S-LINE',
-          \ '' : 'S-BLOCK',
-          \ }, 'keep')
-
-    call s:check_defined('g:airline_theme_map', {})
-    call extend(g:airline_theme_map, {
-          \ 'Tomorrow.*': 'tomorrow',
-          \ 'mo[l|n]okai': 'molokai',
-          \ 'wombat.*': 'wombat',
-          \ '.*solarized.*': 'solarized',
-          \ }, 'keep')
-
-    call airline#extensions#load()
-
-    if !exists('g:airline_section_a')
-      let g:airline_section_a = airline#section#create_left(['mode', 'paste', 'iminsert'])
-    endif
-    if !exists('g:airline_section_b')
-      let g:airline_section_b = airline#section#create(['hunks', 'branch'])
-    endif
-    let g:airline_section_c = airline#section#create(['%<', 'file'])
-    let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
-    let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
-    let g:airline_section_y = airline#section#create(['ffenc'])
-    let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
-    let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
+    call airline#init#bootstrap()
 
     let s:airline_theme_defined = exists('g:airline_theme')
     if s:airline_theme_defined || !airline#switch_matching_theme()

From 2d049949f0573f38a996fa21f0c1af13c98b0965 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:58:29 +0000
Subject: [PATCH 07/20] fix indentation.

---
 plugin/airline.vim | 77 +++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 38 deletions(-)

diff --git a/plugin/airline.vim b/plugin/airline.vim
index f1164da..055c065 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -54,47 +54,48 @@ function! s:airline_toggle()
       au!
     augroup END
     augroup! airline
-      if exists("s:stl")
-        let &stl = s:stl
-      endif
-    else
-      let s:stl = &stl
-      augroup airline
-        autocmd!
 
-        autocmd CmdwinEnter *
-              \ call airline#add_statusline_func('airline#cmdwinenter')
-              \ | call <sid>on_window_changed()
-        autocmd CmdwinLeave * call airline#remove_statusline_func('airline#cmdwinenter')
-
-        autocmd ColorScheme * call <sid>on_colorscheme_changed()
-        autocmd WinEnter,BufWinEnter,FileType,BufUnload,ShellCmdPost,VimResized *
-              \ call <sid>on_window_changed()
-
-        autocmd BufWritePost */autoload/airline/themes/*.vim
-              \ exec 'source '.split(globpath(&rtp, 'autoload/airline/themes/'.g:airline_theme.'.vim', 1), "\n")[0]
-              \ | call airline#load_theme()
-      augroup END
-      if s:airline_initialized
-        call <sid>on_window_changed()
-      endif
+    if exists("s:stl")
+      let &stl = s:stl
     endif
-  endfunction
+  else
+    let s:stl = &stl
+    augroup airline
+      autocmd!
 
-  function! s:get_airline_themes(a, l, p)
-    let files = split(globpath(&rtp, 'autoload/airline/themes/'.a:a.'*'), "\n")
-    return map(files, 'fnamemodify(v:val, ":t:r")')
-  endfunction
-  function! s:airline_theme(...)
-    if a:0
-      call airline#switch_theme(a:1)
-    else
-      echo g:airline_theme
+      autocmd CmdwinEnter *
+            \ call airline#add_statusline_func('airline#cmdwinenter')
+            \ | call <sid>on_window_changed()
+      autocmd CmdwinLeave * call airline#remove_statusline_func('airline#cmdwinenter')
+
+      autocmd ColorScheme * call <sid>on_colorscheme_changed()
+      autocmd WinEnter,BufWinEnter,FileType,BufUnload,ShellCmdPost,VimResized *
+            \ call <sid>on_window_changed()
+
+      autocmd BufWritePost */autoload/airline/themes/*.vim
+            \ exec 'source '.split(globpath(&rtp, 'autoload/airline/themes/'.g:airline_theme.'.vim', 1), "\n")[0]
+            \ | call airline#load_theme()
+    augroup END
+    if s:airline_initialized
+      call <sid>on_window_changed()
     endif
-  endfunction
-  command! -nargs=? -complete=customlist,<sid>get_airline_themes AirlineTheme call <sid>airline_theme(<f-args>)
-  command! AirlineToggleWhitespace call airline#extensions#whitespace#toggle()
-  command! AirlineToggle call <sid>airline_toggle()
+  endif
+endfunction
 
-  call <sid>airline_toggle()
+function! s:get_airline_themes(a, l, p)
+  let files = split(globpath(&rtp, 'autoload/airline/themes/'.a:a.'*'), "\n")
+  return map(files, 'fnamemodify(v:val, ":t:r")')
+endfunction
+function! s:airline_theme(...)
+  if a:0
+    call airline#switch_theme(a:1)
+  else
+    echo g:airline_theme
+  endif
+endfunction
+command! -nargs=? -complete=customlist,<sid>get_airline_themes AirlineTheme call <sid>airline_theme(<f-args>)
+command! AirlineToggleWhitespace call airline#extensions#whitespace#toggle()
+command! AirlineToggle call <sid>airline_toggle()
+
+call <sid>airline_toggle()
 

From 19910a26cbd67aeeda24a56efeca010e7195cd22 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:59:46 +0000
Subject: [PATCH 08/20] check existence of all variables.

---
 autoload/airline/init.vim | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
index cb53f5e..a08542b 100644
--- a/autoload/airline/init.vim
+++ b/autoload/airline/init.vim
@@ -77,11 +77,23 @@ function! airline#init#bootstrap()
   if !exists('g:airline_section_b')
     let g:airline_section_b = airline#section#create(['hunks', 'branch'])
   endif
-  let g:airline_section_c = airline#section#create(['%<', 'file'])
-  let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
-  let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
-  let g:airline_section_y = airline#section#create(['ffenc'])
-  let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
-  let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
+  if !exists('g:airline_section_c')
+    let g:airline_section_c = airline#section#create(['%<', 'file'])
+  endif
+  if !exists('g:airline_section_gutter')
+    let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
+  endif
+  if !exists('g:airline_section_x')
+    let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
+  endif
+  if !exists('g:airline_section_y')
+    let g:airline_section_y = airline#section#create(['ffenc'])
+  endif
+  if !exists('g:airline_section_z')
+    let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+  endif
+  if !exists('g:airline_section_warning')
+    let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
+  endif
 endfunction
 

From c6d996d5cae38c52a4114b9e3e9b23bec73719e1 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 22:07:45 +0000
Subject: [PATCH 09/20] define the rest of the extensions.

---
 autoload/airline/extensions/example.vim    | 4 ++--
 autoload/airline/extensions/syntastic.vim  | 2 +-
 autoload/airline/extensions/tagbar.vim     | 2 +-
 autoload/airline/extensions/whitespace.vim | 2 +-
 autoload/airline/init.vim                  | 9 +--------
 doc/airline.txt                            | 3 ---
 6 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/autoload/airline/extensions/example.vim b/autoload/airline/extensions/example.vim
index d522bd6..0f571f2 100644
--- a/autoload/airline/extensions/example.vim
+++ b/autoload/airline/extensions/example.vim
@@ -11,7 +11,7 @@ function! airline#extensions#example#init(ext)
 
   " Here we define a new part for the plugin.  This allows users to place this
   " extension in arbitrary locations.
-  let g:airline_parts.cats = '%{airline#extensions#example#get_cats()}'
+  call airline#parts#define_raw('cats', '%{airline#extensions#example#get_cats()}')
 
   " Next up we add a funcref so that we can run some code prior to the
   " statusline getting modifed.
@@ -28,7 +28,7 @@ function! airline#extensions#example#apply(...)
     " Let's use a helper function.  It will take care of ensuring that the
     " window-local override exists (and create one based on the global
     " airline_section if not), and prepend to it.
-    call airline#extensions#prepend_to_section('x', g:airline_parts.cats)
+    call airline#extensions#prepend_to_section('x', airline#parts#get('cats').raw)
   endif
 endfunction
 
diff --git a/autoload/airline/extensions/syntastic.vim b/autoload/airline/extensions/syntastic.vim
index 24308c5..a91ec66 100644
--- a/autoload/airline/extensions/syntastic.vim
+++ b/autoload/airline/extensions/syntastic.vim
@@ -10,6 +10,6 @@ function! airline#extensions#syntastic#get_warnings()
 endfunction
 
 function! airline#extensions#syntastic#init(ext)
-  let g:airline_parts.syntastic = '%{airline#extensions#syntastic#get_warnings()}'
+  call airline#parts#define_function('syntastic', 'airline#extensions#syntastic#get_warnings')
 endfunction
 
diff --git a/autoload/airline/extensions/tagbar.vim b/autoload/airline/extensions/tagbar.vim
index 4b51787..214d443 100644
--- a/autoload/airline/extensions/tagbar.vim
+++ b/autoload/airline/extensions/tagbar.vim
@@ -27,6 +27,6 @@ function! airline#extensions#tagbar#init(ext)
   call a:ext.add_inactive_statusline_func('airline#extensions#tagbar#inactive_apply')
   let g:tagbar_status_func = 'airline#extensions#tagbar#get_status'
 
-  let g:airline_parts.tagbar = 'airline#extensions#tagbar#currenttag'
+  call airline#parts#define_function('tagbar', 'airline#extensions#tagbar#currenttag')
 endfunction
 
diff --git a/autoload/airline/extensions/whitespace.vim b/autoload/airline/extensions/whitespace.vim
index 0aa8fbe..234c732 100644
--- a/autoload/airline/extensions/whitespace.vim
+++ b/autoload/airline/extensions/whitespace.vim
@@ -65,7 +65,7 @@ function! airline#extensions#whitespace#toggle()
 endfunction
 
 function! airline#extensions#whitespace#init(...)
-  let g:airline_parts.whitespace = '%{airline#extensions#whitespace#check()}'
+  call airline#parts#define_function('whitespace', 'airline#extensions#whitespace#check')
 
   unlet! b:airline_whitespace_check
   augroup airline_whitespace
diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
index a08542b..80ab516 100644
--- a/autoload/airline/init.vim
+++ b/autoload/airline/init.vim
@@ -37,14 +37,7 @@ function! airline#init#bootstrap()
         \ 'highlight': 'airline_file',
         \ })
   call airline#parts#define_raw('file', '%f%m')
-
-  call s:check_defined('g:airline_parts', {})
-  call extend(g:airline_parts, {
-        \ 'ffenc': '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}',
-        \ 'tagbar': 'airline#parts#empty',
-        \ 'syntastic': 'airline#parts#empty',
-        \ 'whitespace': 'airline#parts#empty',
-        \ }, 'keep')
+  call airline#parts#define_raw('ffenc', '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}')
 
   call s:check_defined('g:airline_mode_map', {})
   call extend(g:airline_mode_map, {
diff --git a/doc/airline.txt b/doc/airline.txt
index 5bcac27..4159728 100644
--- a/doc/airline.txt
+++ b/doc/airline.txt
@@ -388,9 +388,6 @@ For contributions into the plugin, here are the following guidelines:
   b.  Configuration variables for the extension should reside in the
       extension, e.g. `g:airline#extensions#foo_plugin#bar_variable`.
 
-  c.  A value should be added to the `g:airline_parts` dictionary such that
-      the extension can be arbitrarily positioned.
-
 See the source of |example.vim| for a working extension.
 
 ==============================================================================

From cb774fcfd02bd623e710cf1f1c9bdaaa541d1bc6 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 22:10:04 +0000
Subject: [PATCH 10/20] use correct direction of separators.

---
 autoload/airline/init.vim  | 8 ++++----
 autoload/airline/parts.vim | 4 ----
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
index 80ab516..8302e6e 100644
--- a/autoload/airline/init.vim
+++ b/autoload/airline/init.vim
@@ -77,16 +77,16 @@ function! airline#init#bootstrap()
     let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
   endif
   if !exists('g:airline_section_x')
-    let g:airline_section_x = airline#section#create(['tagbar', '%{&filetype}'])
+    let g:airline_section_x = airline#section#create_right(['tagbar', '%{&filetype}'])
   endif
   if !exists('g:airline_section_y')
-    let g:airline_section_y = airline#section#create(['ffenc'])
+    let g:airline_section_y = airline#section#create_right(['ffenc'])
   endif
   if !exists('g:airline_section_z')
-    let g:airline_section_z = airline#section#create(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    let g:airline_section_z = airline#section#create_right(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
   endif
   if !exists('g:airline_section_warning')
-    let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
+    let g:airline_section_warning = airline#section#create_right(['syntastic', 'whitespace'])
   endif
 endfunction
 
diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index 42ab21e..31a9f16 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -24,10 +24,6 @@ function! airline#parts#get(key)
   return get(s:parts, a:key, {})
 endfunction
 
-function! airline#parts#empty()
-  return ''
-endfunction
-
 function! airline#parts#mode()
   return get(w:, 'airline_current_mode', '')
 endfunction

From 0548aeefcbc30d0a4e40819a65babc0e67040628 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 20:26:42 -0400
Subject: [PATCH 11/20] basic tests and travis integration.

---
 .gitignore  |  1 +
 .travis.yml |  4 ++++
 Gemfile     |  2 ++
 README.md   |  2 ++
 Rakefile    | 14 ++++++++++++++
 t/init.vim  | 37 +++++++++++++++++++++++++++++++++++++
 6 files changed, 60 insertions(+)
 create mode 100644 .travis.yml
 create mode 100644 Gemfile
 create mode 100644 Rakefile
 create mode 100644 t/init.vim

diff --git a/.gitignore b/.gitignore
index 926ccaa..66fb17d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 doc/tags
+*.lock
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..9ed483e
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,4 @@
+language: ruby
+rvm:
+  - 1.9.3
+script: rake ci
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..088f22e
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,2 @@
+source 'https://rubygems.org'
+gem 'vim-flavor', '~> 1.1'
diff --git a/README.md b/README.md
index 161b7e6..57cf16f 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,8 @@ Lean &amp; mean statusline for vim that's light as air.
 *  supports 7.2 as the minimum Vim version
 *  predictable release cycle; the master branch is experimental and may break from time to time, if you prefer stability, use the most recent tag which usually is released once every 2 weeks.
 
+[![Build Status](https://travis-ci.org/bling/vim-airline.png)](https://travis-ci.org/bling/vim-airline)
+
 # Straightforward customization
 
 If you don't like the defaults, you can replace all sections with standard `statusline` syntax.  Give your statusline that you've built over the years a face lift.
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..741cfc2
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,14 @@
+#!/usr/bin/env rake
+
+task :default => [:test]
+
+task :ci => [:dump, :test]
+
+task :dump do
+  sh 'vim --version'
+end
+
+task :test do
+  sh 'bundle exec vim-flavor test'
+end
+
diff --git a/t/init.vim b/t/init.vim
new file mode 100644
index 0000000..8aa4e1e
--- /dev/null
+++ b/t/init.vim
@@ -0,0 +1,37 @@
+for key in ['a', 'b', 'c', 'gutter', 'x', 'y', 'z', 'warning']
+  unlet! g:airline_section_{key}
+endfor
+call airline#init#bootstrap()
+
+describe 'init'
+  it 'section a should have mode, paste, iminsert'
+    Expect g:airline_section_a =~ 'mode'
+    Expect g:airline_section_a =~ 'paste'
+    Expect g:airline_section_a =~ 'iminsert'
+  end
+
+  it 'section b should have hunks and branch'
+    Expect g:airline_section_b =~ 'hunks'
+    Expect g:airline_section_b =~ 'branch'
+  end
+
+  it 'section c should be file'
+    Expect g:airline_section_c == '%<%f%m'
+  end
+
+  it 'section x should be filetype'
+    Expect g:airline_section_x =~ '&filetype'
+  end
+
+  it 'section y should be fenc and ff'
+    Expect g:airline_section_y =~ 'ff'
+    Expect g:airline_section_y =~ 'fenc'
+  end
+
+  it 'section z should be line numbers'
+    Expect g:airline_section_z =~ '%3p%%'
+    Expect g:airline_section_z =~ '%3l'
+    Expect g:airline_section_z =~ '%3c'
+  end
+end
+

From 54ec1f39ca1ee01c511d7d942d962a62177aa9b9 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 20:57:34 -0400
Subject: [PATCH 12/20] test some commands

---
 autoload/airline/extensions/whitespace.vim |  1 +
 t/commands.vim                             | 26 ++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 t/commands.vim

diff --git a/autoload/airline/extensions/whitespace.vim b/autoload/airline/extensions/whitespace.vim
index 234c732..3766f4e 100644
--- a/autoload/airline/extensions/whitespace.vim
+++ b/autoload/airline/extensions/whitespace.vim
@@ -56,6 +56,7 @@ endfunction!
 function! airline#extensions#whitespace#toggle()
   if s:enabled
     autocmd! airline_whitespace CursorHold,BufWritePost
+    augroup! airline_whitespace
     let s:enabled = 0
   else
     call airline#extensions#whitespace#init()
diff --git a/t/commands.vim b/t/commands.vim
new file mode 100644
index 0000000..8038ffd
--- /dev/null
+++ b/t/commands.vim
@@ -0,0 +1,26 @@
+call airline#init#bootstrap()
+source plugin/airline.vim
+
+describe 'commands'
+  it 'should toggle off and on'
+    execute 'AirlineToggle'
+    Expect exists('#airline') to_be_false
+    execute 'AirlineToggle'
+    Expect exists('#airline') to_be_true
+  end
+
+  it 'should toggle whitespace off and on'
+    execute 'AirlineToggleWhitespace'
+    Expect exists('#airline_whitespace') to_be_false
+    execute 'AirlineToggleWhitespace'
+    Expect exists('#airline_whitespace') to_be_true
+  end
+
+  it 'should display theme name with no args'
+    execute 'AirlineTheme simple'
+    Expect g:airline_theme == 'simple'
+    execute 'AirlineTheme dark'
+    Expect g:airline_theme == 'dark'
+  end
+end
+

From f5885bf9c2ae12a9f1b74f1e57fa4adaf8d3f20c Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:15:41 -0400
Subject: [PATCH 13/20] test creation of sections

---
 autoload/airline/section.vim |  6 +++---
 t/parts.vim                  | 24 ++++++++++++++++++++++++
 t/section.vim                | 28 ++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 t/parts.vim
 create mode 100644 t/section.vim

diff --git a/autoload/airline/section.vim b/autoload/airline/section.vim
index 788b443..d14a828 100644
--- a/autoload/airline/section.vim
+++ b/autoload/airline/section.vim
@@ -2,7 +2,6 @@
 " vim: et ts=2 sts=2 sw=2
 
 function! s:get_val(key, append)
-  let val = ''
   let part = airline#parts#get(a:key)
   if exists('part.function')
     let func = (part.function).'()'
@@ -14,12 +13,13 @@ function! s:get_val(key, append)
     return a:key
   endif
 
+  let val = ''
   if a:append > 0
     let val .= '%{airline#util#append('.func.')}'
   elseif a:append < 0
-    return '%{airline#util#prepend('.func.')}'
+    let val .= '%{airline#util#prepend('.func.')}'
   else
-    return '%{'.func.'}'
+    let val .= '%{'.func.'}'
   endif
   return val
 endfunction
diff --git a/t/parts.vim b/t/parts.vim
new file mode 100644
index 0000000..03fee1e
--- /dev/null
+++ b/t/parts.vim
@@ -0,0 +1,24 @@
+describe 'parts'
+  it 'overwrites existing values'
+    call airline#parts#define('foo', { 'test': '123' })
+    Expect airline#parts#get('foo').test == '123'
+    call airline#parts#define('foo', { 'test': '321' })
+    Expect airline#parts#get('foo').test == '321'
+  end
+
+  it 'can define a function part'
+    call airline#parts#define_function('func', 'bar')
+    Expect airline#parts#get('func').function == 'bar'
+  end
+
+  it 'can define a text part'
+    call airline#parts#define_text('text', 'bar')
+    Expect airline#parts#get('text').text == 'bar'
+  end
+
+  it 'can define a raw part'
+    call airline#parts#define_raw('raw', 'bar')
+    Expect airline#parts#get('raw').raw == 'bar'
+  end
+end
+
diff --git a/t/section.vim b/t/section.vim
new file mode 100644
index 0000000..0a16105
--- /dev/null
+++ b/t/section.vim
@@ -0,0 +1,28 @@
+call airline#init#bootstrap()
+
+function! SectionSpec()
+endfunction
+
+describe 'section'
+  before
+    call airline#parts#define_text('text', 'text')
+    call airline#parts#define_raw('raw', 'raw')
+    call airline#parts#define_function('func', 'SectionSpec')
+  end
+
+  it 'should create sections with no separators'
+    let s = airline#section#create(['text', 'raw', 'func'])
+    Expect s == '%{"text"}raw%{SectionSpec()}'
+  end
+
+  it 'should create left sections with separators'
+    let s = airline#section#create_left(['text', 'text'])
+    Expect s == '%{"text"}%{airline#util#append("text")}'
+  end
+
+  it 'should create right sections with separators'
+    let s = airline#section#create_right(['text', 'text'])
+    Expect s == '%{airline#util#prepend("text")}%{"text"}'
+  end
+end
+

From b4cd0ae99d97f00ce72de56e8a07be50c40bc60c Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:28:38 -0400
Subject: [PATCH 14/20] add tests for the builder

---
 t/builder.vim | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 t/init.vim    | 30 ++++++++++++++++++++++++++----
 2 files changed, 73 insertions(+), 4 deletions(-)
 create mode 100644 t/builder.vim

diff --git a/t/builder.vim b/t/builder.vim
new file mode 100644
index 0000000..b96d8de
--- /dev/null
+++ b/t/builder.vim
@@ -0,0 +1,47 @@
+call airline#init#bootstrap()
+
+describe 'active builder'
+  before
+    let s:builder = airline#builder#new({'active': 1})
+  end
+
+  it 'should have a call to check mode'
+    let stl = s:builder.build()
+    Expect stl =~ '%{airline#check_mode()}'
+  end
+
+  it 'should transition colors from one to the next'
+    call s:builder.add_section('Normal', 'hello')
+    call s:builder.add_section('NonText', 'world')
+    let stl = s:builder.build()
+    Expect stl =~ '%#Normal#hello%#Normal_to_NonText#>%#NonText#world'
+  end
+
+  it 'should split left/right sections'
+    call s:builder.split()
+    let stl = s:builder.build()
+    Expect stl =~ '%='
+  end
+
+  it 'after split, sections use the right separator'
+    call s:builder.split()
+    call s:builder.add_section('Normal', 'hello')
+    call s:builder.add_section('NonText', 'world')
+    let stl = s:builder.build()
+    Expect stl =~ '%#Normal#hello%#Normal_to_NonText#<%#NonText#world'
+  end
+end
+
+describe 'inactive builder'
+  before
+    let s:builder = airline#builder#new({'active': 0})
+  end
+
+  it 'should transition colors from one to the next'
+    call s:builder.add_section('Normal', 'hello')
+    call s:builder.add_section('NonText', 'world')
+    let stl = s:builder.build()
+    Expect stl =~ '%#Normal_inactive#hello%#Normal_to_NonText_inactive#>%#NonText_inactive#world'
+  end
+end
+
diff --git a/t/init.vim b/t/init.vim
index 8aa4e1e..72a42f6 100644
--- a/t/init.vim
+++ b/t/init.vim
@@ -1,9 +1,21 @@
-for key in ['a', 'b', 'c', 'gutter', 'x', 'y', 'z', 'warning']
-  unlet! g:airline_section_{key}
-endfor
-call airline#init#bootstrap()
+let s:sections = ['a', 'b', 'c', 'gutter', 'x', 'y', 'z', 'warning']
+
+function! s:clear()
+  for key in s:sections
+    unlet! g:airline_section_{key}
+  endfor
+endfunction
 
 describe 'init'
+  before
+    call s:clear()
+    call airline#init#bootstrap()
+  end
+
+  after
+    call s:clear()
+  end
+
   it 'section a should have mode, paste, iminsert'
     Expect g:airline_section_a =~ 'mode'
     Expect g:airline_section_a =~ 'paste'
@@ -33,5 +45,15 @@ describe 'init'
     Expect g:airline_section_z =~ '%3l'
     Expect g:airline_section_z =~ '%3c'
   end
+
+  it 'should not redefine sections already defined'
+    for s in s:sections
+      let g:airline_section_{s} = s
+    endfor
+    call airline#init#bootstrap()
+    for s in s:sections
+      Expect g:airline_section_{s} == s
+    endfor
+  end
 end
 

From e852fb388f7002f57b066404569c58a29b23e47d Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 21:42:42 -0400
Subject: [PATCH 15/20] test util functions

---
 t/util.vim | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 t/util.vim

diff --git a/t/util.vim b/t/util.vim
new file mode 100644
index 0000000..511c7fd
--- /dev/null
+++ b/t/util.vim
@@ -0,0 +1,41 @@
+call airline#init#bootstrap()
+
+function! Util1()
+  let g:count += 1
+endfunction
+function! Util2()
+  let g:count += 2
+endfunction
+function! Util3(...)
+  let g:count = a:0
+endfunction
+
+describe 'util'
+  before
+    let g:count = 0
+  end
+
+  it 'has append wrapper function'
+    Expect airline#util#append('') == ''
+    Expect airline#util#append('1') == '  > 1'
+  end
+
+  it 'has prepend wrapper function'
+    Expect airline#util#prepend('') == ''
+    Expect airline#util#prepend('1') == '1 < '
+  end
+
+  it 'has getwinvar function'
+    Expect airline#util#getwinvar(1, '&statusline', 'foo') == getwinvar(1, '&statusline')
+    Expect airline#util#getwinvar(1, 'asdf', '123') == '123'
+  end
+
+  it 'has exec funcrefs helper functions'
+    call airline#util#exec_funcrefs([function('Util1'), function('Util2')])
+    Expect g:count == 3
+
+    call airline#util#exec_funcrefs([function('Util3')], 1, 2, 3, 4)
+    Expect g:count == 4
+  end
+end
+

From d2687440776790c2b695be97f6e1a2d0a6571030 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Fri, 30 Aug 2013 22:44:20 -0400
Subject: [PATCH 16/20] test the layout config for the default extension.

---
 .gitignore                             |  1 +
 autoload/airline/extensions/branch.vim |  4 +++-
 t/extensions_default.vim               | 22 ++++++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 t/extensions_default.vim

diff --git a/.gitignore b/.gitignore
index 66fb17d..296f094 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 doc/tags
 *.lock
+.vim-flavor
diff --git a/autoload/airline/extensions/branch.vim b/autoload/airline/extensions/branch.vim
index 446c89d..0aa3da5 100644
--- a/autoload/airline/extensions/branch.vim
+++ b/autoload/airline/extensions/branch.vim
@@ -27,7 +27,9 @@ function! airline#extensions#branch#get_head()
     endif
   endif
 
-  return empty(head) ? s:empty_message : s:symbol.' '.head
+  return empty(head)
+        \ ? s:empty_message
+        \ : printf('%s%s', empty(s:symbol) ? '' : s:symbol.' ', head)
 endfunction
 
 function! airline#extensions#branch#init(ext)
diff --git a/t/extensions_default.vim b/t/extensions_default.vim
new file mode 100644
index 0000000..9eb8023
--- /dev/null
+++ b/t/extensions_default.vim
@@ -0,0 +1,22 @@
+call airline#init#bootstrap()
+
+describe 'default'
+  before
+    let s:builder = airline#builder#new({'active': 1})
+  end
+
+  it 'should use the layout'
+    let g:airline#extensions#default#layout = [
+          \ [ 'c', 'a', 'b', 'warning' ],
+          \ [ 'x', 'z', 'y' ]
+          \ ]
+    call airline#extensions#default#apply(s:builder, { 'winnr': 1, 'active': 1 })
+    let stl = s:builder.build()
+    Expect stl =~ 'airline_c_to_airline_a'
+    Expect stl =~ 'airline_a_to_airline_b'
+    Expect stl =~ 'airline_b_to_airline_warning'
+    Expect stl =~ 'airline_x_to_airline_z'
+    Expect stl =~ 'airline_z_to_airline_y'
+  end
+end
+

From 500ecf7cd08c5883baecb640340814751ab6026e Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Sat, 31 Aug 2013 03:26:59 +0000
Subject: [PATCH 17/20] support for prefixing with a highlight group.

---
 autoload/airline/section.vim | 10 ++++++++--
 t/section.vim                |  9 +++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/autoload/airline/section.vim b/autoload/airline/section.vim
index d14a828..3df4bbe 100644
--- a/autoload/airline/section.vim
+++ b/autoload/airline/section.vim
@@ -3,17 +3,23 @@
 
 function! s:get_val(key, append)
   let part = airline#parts#get(a:key)
+
+  let val = ''
+  if exists('part.highlight')
+    let val .= '%#'.(part.highlight).'#'
+  endif
+
   if exists('part.function')
     let func = (part.function).'()'
   elseif exists('part.text')
     let func = '"'.(part.text).'"'
   elseif exists('part.raw')
-    return part.raw
+    return val.(part.raw)
   else
     return a:key
   endif
 
-  let val = ''
+
   if a:append > 0
     let val .= '%{airline#util#append('.func.')}'
   elseif a:append < 0
diff --git a/t/section.vim b/t/section.vim
index 0a16105..433dc0a 100644
--- a/t/section.vim
+++ b/t/section.vim
@@ -8,6 +8,10 @@ describe 'section'
     call airline#parts#define_text('text', 'text')
     call airline#parts#define_raw('raw', 'raw')
     call airline#parts#define_function('func', 'SectionSpec')
+    call airline#parts#define('hi', {
+          \ 'raw': 'hello',
+          \ 'highlight': 'hlgroup',
+          \ })
   end
 
   it 'should create sections with no separators'
@@ -24,5 +28,10 @@ describe 'section'
     let s = airline#section#create_right(['text', 'text'])
     Expect s == '%{airline#util#prepend("text")}%{"text"}'
   end
+
+  it 'should prefix with highlight group if provided'
+    let s = airline#section#create(['hi'])
+    Expect s == '%#hlgroup#hello'
+  end
 end
 

From a13c6925297b645d399f97c00c865ed21afe9d50 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Sat, 31 Aug 2013 03:35:23 +0000
Subject: [PATCH 18/20] define default statusline items with empty contents.

---
 autoload/airline/init.vim  | 40 ++++++++++++++++++++------------------
 autoload/airline/parts.vim |  6 ++++++
 t/init.vim                 | 12 +++++++++---
 3 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
index 8302e6e..c1ac79f 100644
--- a/autoload/airline/init.vim
+++ b/autoload/airline/init.vim
@@ -20,25 +20,6 @@ function! airline#init#bootstrap()
   call s:check_defined('g:airline_exclude_filetypes', [])
   call s:check_defined('g:airline_exclude_preview', 0)
 
-  call s:check_defined('g:airline_symbols', {})
-  call extend(g:airline_symbols, {
-        \ 'paste': get(g:, 'airline_paste_symbol', 'PASTE'),
-        \ 'readonly': get(g:, 'airline_readonly_symbol', get(g:, 'airline_powerline_fonts', 0) ? '' : 'RO'),
-        \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? '✹' : '!',
-        \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
-        \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
-        \ }, 'keep')
-
-  call airline#parts#define_function('mode', 'airline#parts#mode')
-  call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
-  call airline#parts#define_function('paste', 'airline#parts#paste')
-  call airline#parts#define('readonly', {
-        \ 'function': 'airline#parts#readonly',
-        \ 'highlight': 'airline_file',
-        \ })
-  call airline#parts#define_raw('file', '%f%m')
-  call airline#parts#define_raw('ffenc', '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}')
-
   call s:check_defined('g:airline_mode_map', {})
   call extend(g:airline_mode_map, {
         \ '__' : '------',
@@ -62,6 +43,27 @@ function! airline#init#bootstrap()
         \ '.*solarized.*': 'solarized',
         \ }, 'keep')
 
+  call s:check_defined('g:airline_symbols', {})
+  call extend(g:airline_symbols, {
+        \ 'paste': get(g:, 'airline_paste_symbol', 'PASTE'),
+        \ 'readonly': get(g:, 'airline_readonly_symbol', get(g:, 'airline_powerline_fonts', 0) ? '' : 'RO'),
+        \ 'whitespace': get(g:, 'airline_powerline_fonts', 0) ? '✹' : '!',
+        \ 'linenr': get(g:, 'airline_linecolumn_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ':' ),
+        \ 'branch': get(g:, 'airline_branch_prefix', get(g:, 'airline_powerline_fonts', 0) ? '' : ''),
+        \ }, 'keep')
+
+  call airline#parts#define_function('mode', 'airline#parts#mode')
+  call airline#parts#define_function('iminsert', 'airline#parts#iminsert')
+  call airline#parts#define_function('paste', 'airline#parts#paste')
+  call airline#parts#define('readonly', {
+        \ 'function': 'airline#parts#readonly',
+        \ 'highlight': 'airline_file',
+        \ })
+  call airline#parts#define_raw('file', '%f%m')
+  call airline#parts#define_raw('ffenc', '%{printf("%s%s",&fenc,strlen(&ff)>0?"[".&ff."]":"")}')
+
+  call airline#parts#define_empty(['hunks', 'branch', 'tagbar', 'syntastic'])
+
   call airline#extensions#load()
 
   if !exists('g:airline_section_a')
diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index 31a9f16..39041f8 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -20,6 +20,12 @@ function! airline#parts#define_raw(key, raw)
   call airline#parts#define(a:key, { 'raw': a:raw })
 endfunction
 
+function! airline#parts#define_empty(keys)
+  for key in a:keys
+    call airline#parts#define_raw(key, '')
+  endfor
+endfunction
+
 function! airline#parts#get(key)
   return get(s:parts, a:key, {})
 endfunction
diff --git a/t/init.vim b/t/init.vim
index 72a42f6..f529381 100644
--- a/t/init.vim
+++ b/t/init.vim
@@ -22,9 +22,8 @@ describe 'init'
     Expect g:airline_section_a =~ 'iminsert'
   end
 
-  it 'section b should have hunks and branch'
-    Expect g:airline_section_b =~ 'hunks'
-    Expect g:airline_section_b =~ 'branch'
+  it 'section b should be blank because no extensions are installed'
+    Expect g:airline_section_b == ''
   end
 
   it 'section c should be file'
@@ -55,5 +54,12 @@ describe 'init'
       Expect g:airline_section_{s} == s
     endfor
   end
+
+  it 'all default statusline extensions should be blank'
+    Expect airline#parts#get('hunks').raw == ''
+    Expect airline#parts#get('branch').raw == ''
+    Expect airline#parts#get('tagbar').raw == ''
+    Expect airline#parts#get('syntastic').raw == ''
+  end
 end
 

From 7bcb9b5fffb57605632fb1082e46c85355c6cdfa Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Sat, 31 Aug 2013 03:41:19 +0000
Subject: [PATCH 19/20] more compatible test for older vim version.

---
 autoload/airline/section.vim | 1 -
 t/util.vim                   | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/autoload/airline/section.vim b/autoload/airline/section.vim
index 3df4bbe..1c7e789 100644
--- a/autoload/airline/section.vim
+++ b/autoload/airline/section.vim
@@ -19,7 +19,6 @@ function! s:get_val(key, append)
     return a:key
   endif
 
-
   if a:append > 0
     let val .= '%{airline#util#append('.func.')}'
   elseif a:append < 0
diff --git a/t/util.vim b/t/util.vim
index 511c7fd..60606c7 100644
--- a/t/util.vim
+++ b/t/util.vim
@@ -26,8 +26,9 @@ describe 'util'
   end
 
   it 'has getwinvar function'
-    Expect airline#util#getwinvar(1, '&statusline', 'foo') == getwinvar(1, '&statusline')
     Expect airline#util#getwinvar(1, 'asdf', '123') == '123'
+    call setwinvar(1, 'vspec', 'is cool')
+    Expect airline#util#getwinvar(1, 'vspec', '') == 'is cool'
   end
 
   it 'has exec funcrefs helper functions'

From a249c87f616f08bb98a562ffe77402d48e06a048 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Sat, 31 Aug 2013 04:54:52 +0000
Subject: [PATCH 20/20] separators unnecessary in warning section.

---
 autoload/airline/init.vim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/autoload/airline/init.vim b/autoload/airline/init.vim
index c1ac79f..50551f4 100644
--- a/autoload/airline/init.vim
+++ b/autoload/airline/init.vim
@@ -88,7 +88,7 @@ function! airline#init#bootstrap()
     let g:airline_section_z = airline#section#create_right(['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
   endif
   if !exists('g:airline_section_warning')
-    let g:airline_section_warning = airline#section#create_right(['syntastic', 'whitespace'])
+    let g:airline_section_warning = airline#section#create(['syntastic', 'whitespace'])
   endif
 endfunction