Simplify the code for escaping strings for Windows

autoload/ale.vim

@@ -155,25 +155,20 @@ function! ale#Set(variable_name, default) abort
     return l:value
 endfunction
 
-function! s:EscapePercents(str) abort
-    return substitute(a:str, '%', '%%', 'g')
-endfunction
-
 " Escape a string suitably for each platform.
 " shellescape does not work on Windows.
 function! ale#Escape(str) abort
     if fnamemodify(&shell, ':t') ==? 'cmd.exe'
-        if a:str =~# '\v^[a-zA-Z0-9-_\\/:%]+$'
+        " If the string contains spaces, it will be surrounded by quotes.
-            return s:EscapePercents(a:str)
+        " Otherwise, special characters will be escaped with carets (^).
-        endif
+        return substitute(
-
+        \   a:str =~# ' '
-        if a:str =~# ' '
+        \       ?  '"' .  substitute(a:str, '"', '""', 'g') . '"'
-            return '"'
+        \       : substitute(a:str, '\v([&|<>^])', '^\1', 'g'),
-            \   .  substitute(s:EscapePercents(a:str), '"', '""', 'g')
+        \   '%',
-            \   . '"'
+        \   '%%',
-        endif
+        \   'g',
-
+        \)
-        return s:EscapePercents(substitute(a:str, '\v([&|<>^])', '^\1', 'g'))
     endif
 
     return shellescape (a:str)