diff --git a/src/fsh.nim b/src/fsh.nim
index 51fd803..3787401 100644
--- a/src/fsh.nim
+++ b/src/fsh.nim
@@ -192,7 +192,8 @@ proc readVariable(strm: Stream): string =
 # evalVariable finds a value of a variable
 proc evalVariable(vari: string): string =
   if vari == "$": return "$"
-  for frame in shellVariables:
+  for i in shellVariables.high..shellVariables.low:
+    let frame = shellVariables[i]
     if frame.hasKey(vari): return frame[vari]
   if envVariables.hasKey(vari):
     result = envVariables[vari]