reverting Scope#temporary simplification.

Author: jashkenas

lib/grammar.js

@@ -55,7 +55,10 @@ exports.Scope = class Scope
 
   # Generate a temporary variable name at the given index.
   temporary: (name, index) ->
-    '_' + name + if index > 1 then index else ''
+    if name.length > 1
+      '_' + name + if index > 1 then index else ''
+    else
+      '_' + (index + parseInt name, 36).toString(36).replace /\d/g, 'a'
 
   # Gets the type of a variable.
   type: (name) ->