anchor.diff:  
   --------------------------------------------------------
   declare-option range-specs my_range
  -set-option window my_range "%val{timestamp}:1.1,1.3|red"
  +set-option window my_range %val{timestamp} '1.1,1.3|red'
   add-highlighter window/ ranges my_range
   --------------------------------------------------------
   
  
positive.code:     In this example two words will be added in the gutter: a blue Foo at
      line 1 and a bold red/yellow Bar on line 3:
  
  ----------------------------------------------------------------------
  declare-option line-specs my_flags
  set-option window my_flags "%val{timestamp}:1|Foo:3|{red,yellow+b}Bar"
  add-highlighter window/ flag-lines blue my_flags
  ----------------------------------------------------------------------
  
  *ranges* <option_name>::
      use the data in the `range-specs` option of the given name to highlight
  
negative.code: 
  --------------------------------------------------------
  declare-option range-specs my_range
  set-option window my_range %val{timestamp} '1.1,1.3|red'
  add-highlighter window/ replace-ranges my_range
  --------------------------------------------------------
  
  