fixes #109, replace eval by str2nr

plugin/ack.vim

@@ -10,17 +10,17 @@
 " Location of the ack utility
 if !exists("g:ackprg")
   let s:ack_default_options = "-s -H --nocolor --nogroup --column"
-  if executable('ack-grep')
-    let g:ackprg = "ack-grep"
-  elseif executable('ack')
+  if executable('ack')
     let g:ackprg = "ack"
+  elseif executable('ack-grep')
+    let g:ackprg = "ack-grep"
   else
     finish
   endif
   let g:ackprg .= s:ack_default_options
 endif
 
-let s:ackprg_version = eval(matchstr(system(g:ackprg . " --version"),  '[0-9.]\+'))
+let s:ackprg_version = str2nr(matchstr(system(g:ackprg . " --version"),  '[0-9.]\+'))
 
 if !exists("g:ack_apply_qmappings")
   let g:ack_apply_qmappings = !exists("g:ack_qhandler")
@@ -64,7 +64,7 @@ function! s:Ack(cmd, args)
   let grepformat_bak=&grepformat
   try
     let l:ackprg_run = g:ackprg
-    if a:cmd =~# '-g$' && s:ackprg_version > 2
+    if a:cmd =~# '-g$' && s:ackprg_version >= 2
       " remove arguments that conflict with -g
       let l:ackprg_run = substitute(l:ackprg_run, '-H\|--column', '', 'g')
     end