correctly inject the accent highlight groups.

autoload/airline/builder.vim

@@ -23,7 +23,8 @@ function! s:prototype.add_section(group, contents)
     let self._line .= '%#'.a:group.'#'
   endif
 
-  let self._line .= a:contents
+  let contents = substitute(a:contents, 'airline_accent', a:group, 'g')
+  let self._line .= contents
   let self._curgroup = a:group
 endfunction
 

autoload/airline/section.vim

@@ -9,8 +9,8 @@ function! s:create(parts, append)
     let part = airline#parts#get(a:parts[idx])
 
     let val = ''
-    if exists('part.highlight')
-      let val .= '%#'.(part.highlight).'#'
+    if exists('part.accent')
+      let val .= '%#airline_accent_'.(part.accent).'#'
     endif
 
     if exists('part.function')

t/builder.vim

@@ -37,6 +37,12 @@ describe 'active builder'
     let stl = s:builder.build()
     Expect stl == '%#Normal#hello>hello'
   end
+
+  it 'should replace accent groups with the specified group'
+    call s:builder.add_section('Normal', '%#airline_accent_foo#hello')
+    let stl = s:builder.build()
+    Expect stl == '%#Normal#%#Normal_foo#hello'
+  end
 end
 
 describe 'inactive builder'

t/section.vim

@@ -26,13 +26,13 @@ describe 'section'
     Expect s == '%{airline#util#prepend("text",0)}%{airline#util#wrap("text",0)}'
   end
 
-  it 'should prefix with highlight group if provided'
+  it 'should prefix with accent group if provided'
     call airline#parts#define('hi', {
           \ 'raw': 'hello',
-          \ 'highlight': 'hlgroup',
+          \ 'accent': 'red',
           \ })
     let s = airline#section#create(['hi'])
-    Expect s == '%#hlgroup#hello'
+    Expect s == '%#airline_accent_red#hello'
   end
 
   it 'should parse out a section from the distro'