much smarter handling of separators (#204).

autoload/airline/init.vim

@@ -58,6 +58,7 @@ function! airline#init#bootstrap()
   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_function('filetype', 'airline#parts#filetype')
   call airline#parts#define('readonly', {
         \ 'function': 'airline#parts#readonly',
         \ 'highlight': 'airline_file',
@@ -83,7 +84,7 @@ function! airline#init#sections()
     let g:airline_section_gutter = airline#section#create([' ', 'readonly', '%='])
   endif
   if !exists('g:airline_section_x')
-    let g:airline_section_x = airline#section#create_right(['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_right(['ffenc'])

autoload/airline/parts.vim

@@ -57,3 +57,7 @@ function! airline#parts#readonly()
   return &readonly ? g:airline_symbols.readonly : ''
 endfunction
 
+function! airline#parts#filetype()
+  return &filetype
+endfunction
+

autoload/airline/section.vim

@@ -3,54 +3,59 @@
 
 call airline#init#bootstrap()
 
-function! s:get_val(key, append)
-  let part = airline#parts#get(a:key)
+function! s:create(parts, append)
+  let _ = ''
+  for idx in range(len(a:parts))
+    let part = airline#parts#get(a:parts[idx])
 
-  let val = ''
-  if exists('part.highlight')
-    let val .= '%#'.(part.highlight).'#'
-  endif
+    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 val.(part.raw)
-  else
-    return a:key
-  endif
+    if exists('part.function')
+      let func = (part.function).'()'
+    elseif exists('part.text')
+      let func = '"'.(part.text).'"'
+    else
+      if a:append > 0 && idx != 0
+        let val .= ' '.g:airline_left_alt_sep.' '
+      endif
+      if a:append < 0 && idx != 0
+        let val = ' '.g:airline_right_alt_sep.' '.val
+      endif
+      if exists('part.raw')
+        let _ .= val.(part.raw)
+        continue
+      else
+        let _ .= val.a:parts[idx]
+        continue
+      endif
+    endif
 
-  let minwidth = get(part, 'minwidth', 0)
+    let minwidth = get(part, 'minwidth', 0)
 
-  if a:append > 0
-    let val .= printf('%%{airline#util#append(%s,%s)}', func, minwidth)
-  elseif a:append < 0
-    let val .= printf('%%{airline#util#prepend(%s,%s)}', func, minwidth)
-  else
-    let val .= printf('%%{airline#util#wrap(%s,%s)}', func, minwidth)
-  endif
-  return val
+    if a:append > 0 && idx != 0
+      let val .= printf('%%{airline#util#append(%s,%s)}', func, minwidth)
+    elseif a:append < 0 && idx != len(a:parts) - 1
+      let val .= printf('%%{airline#util#prepend(%s,%s)}', func, minwidth)
+    else
+      let val .= printf('%%{airline#util#wrap(%s,%s)}', func, minwidth)
+    endif
+    let _ .= val
+  endfor
+  return _
 endfunction
 
 function! airline#section#create(parts)
-  return join(map(a:parts, 's:get_val(v:val, 0)'), '')
+  return s:create(a:parts, 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 _
+  return s:create(a:parts, 1)
 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 _
+  return s:create(a:parts, -1)
 endfunction