Fix b526e4d for ancient rubies

Author: jaynetics

lib/regexp_parser/expression/methods/negative.rb

@@ -10,11 +10,11 @@ def negated?
     end
   end
 
-  Anchor::NonWordBoundary.class_eval       { def negative?; true                   end }
-  Assertion::NegativeLookahead.class_eval  { def negative?; true                   end }
-  Assertion::NegativeLookbehind.class_eval { def negative?; true                   end }
-  CharacterSet.class_eval                  { def negative?; negative               end }
-  CharacterType::Base.class_eval           { def negative?; token.to_s =~ /^non/   end }
-  PosixClass.class_eval                    { def negative?; type == :nonposixclass end }
-  UnicodeProperty::Base.class_eval         { def negative?; type == :nonproperty   end }
+  Anchor::NonWordBoundary.class_eval       { def negative?; true                          end }
+  Assertion::NegativeLookahead.class_eval  { def negative?; true                          end }
+  Assertion::NegativeLookbehind.class_eval { def negative?; true                          end }
+  CharacterSet.class_eval                  { def negative?; negative                      end }
+  CharacterType::Base.class_eval           { def negative?; token.to_s.start_with?('non') end }
+  PosixClass.class_eval                    { def negative?; type == :nonposixclass        end }
+  UnicodeProperty::Base.class_eval         { def negative?; type == :nonproperty          end }
 end