anchor.diff:  
   The supported types include: `integer`, `float`, `string`, and `boolean`.
   
  -`boolean` will set a field to true if its string value is equal to `true` (ignore case), to
  +`boolean` will set the field to true if its string value is equal to `true` (ignore case), to
   false if its string value is equal to `false` (ignore case) and it will throw exception otherwise.
   
   [source,js]
  
positive.code: --------------------------------------------------
  
  ==== Remove processor
  Removes an existing field. If a field doesn't exist, nothing will happen.
  
  [source,js]
  --------------------------------------------------
  
negative.code: --------------------------------------------------
  
  ==== Rename processor
  Renames an existing field. If the field doesn't exist, an exception will be thrown. Also, the new field
  name must not exist.
  
  [source,js]
  