Ability to highlight "changed" part of {code}

Often I want to highlight a specific section of code within a

 macro. But there is user specifyable coloring within 

. Some brainstorming:

• Allow for

   - This would turn off syntax highlighting.
  * Within the macro allow for the use of {color} macro. 
  
  Kinda klunky. Maybe this should not be added to 

  , but rather a sublcass of

  or a new macro altogether so it could have clearer specification.

Does this make any sense?