diff --git a/runtime/indent/treetop.vim b/runtime/indent/treetop.vim
index 01716e7..2c6eecf 100644
--- a/runtime/indent/treetop.vim
+++ b/runtime/indent/treetop.vim
@@ -26,12 +26,12 @@
   let line = getline(pnum)
 
   if line =~ '^\s*\%(grammar\|module\|rule\)\>'
-    let ind += &sw
+    let ind += shiftwidth()
   endif
 
   let line = getline(v:lnum)
   if line =~ '^\s*end\>'
-    let ind -= &sw
+    let ind -= shiftwidth()
   end
 
   retur ind