Refactoring: g:startify_custom_header

autoload/startify.vim

@@ -75,8 +75,11 @@ function! startify#insane_in_the_membrane() abort
   if exists('g:startify_custom_header')
     if type(g:startify_custom_header) == type([])
       let g:startify_header = copy(g:startify_custom_header)
-    else
+    elseif type(g:startify_custom_header) == type('')
       let g:startify_header = eval(g:startify_custom_header)
+    else
+      echomsg 'startify: wrong type of value for g:startify_custom_header'
+      let g:startify_header = startify#fortune#cowsay()
     endif
   else
     let g:startify_header = startify#fortune#cowsay()

autoload/startify/fortune.vim

@@ -28,8 +28,7 @@ endfunction
 " Function: #boxed {{{1
 function! startify#fortune#boxed(...) abort
   let wrapped_quote = []
-  let Quote = a:0 && type(a:1) == type([]) ? a:1 : startify#fortune#quote()
-  let quote = type(Quote) == type(function('tr')) ? Quote() : Quote
+  let quote = a:0 && type(a:1) == type([]) ? a:1 : startify#fortune#quote()
   for line in quote
     let wrapped_quote += split(line, '\%50c.\{-}\zs\s', 1)
   endfor
@@ -40,14 +39,17 @@ endfunction
 " Function: #cowsay {{{1
 function! startify#fortune#cowsay(...) abort
   if a:0
-    let s:char_top_bottom   = get(a:000, 0, s:char_top_bottom)
-    let s:char_sides        = get(a:000, 1, s:char_sides)
-    let s:char_top_left     = get(a:000, 2, s:char_top_left)
-    let s:char_top_right    = get(a:000, 3, s:char_top_right)
-    let s:char_bottom_right = get(a:000, 4, s:char_bottom_right)
-    let s:char_bottom_left  = get(a:000, 5, s:char_bottom_left)
+    let quote = a:0 && type(a:1) == type([]) ? a:1 : startify#fortune#quote()
+    let s:char_top_bottom   = get(a:000, 1, s:char_top_bottom)
+    let s:char_sides        = get(a:000, 2, s:char_sides)
+    let s:char_top_left     = get(a:000, 3, s:char_top_left)
+    let s:char_top_right    = get(a:000, 4, s:char_top_right)
+    let s:char_bottom_right = get(a:000, 5, s:char_bottom_right)
+    let s:char_bottom_left  = get(a:000, 6, s:char_bottom_left)
+  else
+    let quote = startify#fortune#quote()
   endif
-  let boxed_quote = startify#fortune#boxed()
+  let boxed_quote = startify#fortune#boxed(quote)
   let boxed_quote += s:cow
   return map(boxed_quote, '"   ". v:val')
 endfunction

doc/startify.txt

@@ -516,17 +516,23 @@ NOTE: There is no sanitizing going on, so you should know what you're doing!
 ------------------------------------------------------------------------------
                                                       *g:startify_custom_header*
 >
-    let g:startify_custom_header = startify#fortune#cowsay()
+    let g:startify_custom_header = 'startify#fortune#cowsay()'
 <
-This is a list of strings to be shown before everything else. Every string
-will be written on its own line, hence you can use empty strings for blank
-lines.
+Define your own header.
 
-Static example:~
->
-    let g:startify_custom_header = ['line 1', '', 'line 3']
-<
-Static example #2:~
+This option takes a `list of strings`, whereas each string will be put on its
+own line. If it is a simple `string`, it should evaluate to a list of strings.
+
+Helper functions:~
+
+    startify#fortune#quote()       random quote
+    startify#fortune#boxed(...)    random quote in a box
+    startify#fortune#cowsay(...)   random quote in a box + cow
+
+The last two functions optionally take a quote in the list of strings format.
+They also return a list of strings, suitable for this option.
+
+Example #1:~
 >
     let g:startify_custom_header = [
             \ '                                 ________  __ __        ',
@@ -538,21 +544,13 @@ Static example #2:~
             \ '     \/__/    \/_/\/_/\/_/\/_/    \//  \/_/     \/_/    ',
             \ ]
 <
-Dynamic example:~
+Example #2:~
 >
     let g:startify_custom_header =
             \ map(split(system('fortune | cowsay'), '\n'), '"   ". v:val')
 <
-If you go for a dynamic header, you might find the following functions useful:
-
-    startify#fortune#quote()     raw random quote
-    startify#fortune#boxed(...)  opt list or formatted random quote in a box
-    startify#fortune#cowsay()    formatted random quote in a box + cow
+Example #3:~
 
-Try them like this:
->
-    :echo join(startify#fortune#cowsay(), "\n")
-<
 Let's assume you like the default boxed random quote, but not the ASCII art
 cow. You'd rather have another small ASCII art come before the quote. No
 problem!