anchor.diff:  
   Regular expression constants are directly supported:
   
  -[source,js]
  +[source,painless]
   ---------------------------------------------------------
   Pattern p = /[aeiou]/
   ---------------------------------------------------------
   
   Patterns can only be created via this mechanism. This ensures fast performance, regular expressions
  -are always constants and compiled efficiently a single time. 
  +are always constants and compiled efficiently a single time.
   
   [float]
   [[modules-scripting-painless-regex-flags]]
  
positive.code: === Lambda expressions
  Lambda expressions and method references work the same as https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html[Java's].
  
  [source,js]
  ---------------------------------------------------------
  list.removeIf(item -> item == 2);
  list.removeIf((int item) -> item == 2);
  
negative.code: 
  Map keys can also be accessed via subscript (for keys containing special characters):
  
  [source,painless]
  ---------------------------------------------------------
  return map['something-absurd!']
  ---------------------------------------------------------
  