lib/rouge/lexer.rb in rouge-0.2.6 vs lib/rouge/lexer.rb in rouge-0.2.7

@@ -257,12 +257,25 @@
     # information that is unnecessary for lexing in the real world.
     #
     # @example
     #   debug { "hello, world!" }
     def debug(&b)
-      @debug = option(:debug) unless instance_variable_defined?(:@debug)
+      # This method is a hotspot, unfortunately.
+      #
+      # For performance reasons, the "debug" option of a lexer cannot
+      # be changed once it has begun lexing.  This method will redefine
+      # itself on the first call to a noop if "debug" is not set.
+      if option(:debug)
+        class << self
+          def debug; puts yield; end
+        end
+      else
+        class << self
+          def debug; end
+        end
+      end
 
-      puts(b.call) if @debug
+      debug(&b)
     end
 
     # @abstract
     #
     # Called after each lex is finished.  The default implementation