codontable.rb in bio-1.5.0

- old
+ new

@@ -3,11 +3,10 @@
 #
 # Copyright::	Copyright (C) 2001, 2004
 #		Toshiaki Katayama <k@bioruby.org>
 # License::	The Ruby License
 #
-# $Id:$
 #
 # == Data source
 #
 # Data in this class is converted from the NCBI's genetic codes page.
 #
@@ -125,10 +124,10 @@
   #
   #   table = Bio::CodonTable[1]
   #   table.revtrans("A")	# => ["gcg", "gct", "gca", "gcc"]
   #
   def revtrans(aa)
-    unless @reverse
+    unless (defined? @reverse) && @reverse
       @reverse = {}
       @table.each do |k, v|
         @reverse[v] ||= []
         @reverse[v] << k
       end