lazy load variables until needed (#204).

this allows users to define section variables in their vimrc.

autoload/airline/init.vim

@@ -7,7 +7,11 @@ function! s:check_defined(variable, default)
   endif
 endfunction
 
-function! airline#init#bootstrap()
+let s:init_vars = 0
+function airline#init#vars()
+  if s:init_vars | return | endif
+  let s:init_vars = 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)?"":"<")
@@ -51,19 +55,10 @@ function! airline#init#bootstrap()
         \ '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')
+endfunction
 
-  call airline#parts#define_raw('mode', '%{get(w:, "airline_current_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'])
-
+function! airline#init#bootstrap()
+  call airline#init#vars()
   call airline#extensions#load()
 
   if !exists('g:airline_section_a')

autoload/airline/parts.vim

@@ -38,6 +38,10 @@ 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 : ''
 endfunction
@@ -53,3 +57,15 @@ function! airline#parts#readonly()
   return &readonly ? g:airline_symbols.readonly : ''
 endfunction
 
+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'])
+

autoload/airline/util.vim

@@ -1,6 +1,8 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
+call airline#init#vars()
+
 function! airline#util#wrap(text, minwidth)
   if a:minwidth > 0 && winwidth(0) < a:minwidth
     return ''

t/airline.vim

@@ -42,5 +42,11 @@ describe 'airline'
     call airline#update_statusline()
     Expect &statusline =~ 'helloworld'
   end
+
+  it 'should allow users to redefine sections'
+    let g:airline_section_a = airline#section#create(['mode', 'mode'])
+    call airline#update_statusline()
+    Expect &statusline =~ '%{airline#util#wrap(airline#parts#mode(),0)}%{airline#util#wrap(airline#parts#mode(),0)}'
+  end
 end