anchor.diff:  
   p
       |  Let's imagine you wanted to create a tokenizer for a new language. There
  -    |  are four things you would need to define:
  +    |  are five things you would need to define:
   
   +list("numbers")
       +item
  
positive.code:     |  algorithm in Python, optimized for readability rather than performance:
  
  +code.
      def tokenizer_pseudo_code(text, find_prefix, find_suffix,
                                find_infixes, special_cases):
          tokens = []
          for substring in text.split(' '):
              suffixes = []
  
negative.code:     +item
          |  A function #[code infixes_finditer], to handle non-whitespace
          |  separators, such as hyphens etc.
  
      +item
          |  (Optional) A boolean function #[code token_match] matching strings
          |  that should never be split, overriding the previous rules.
          |  Useful for things like URLs or numbers.
  
  p
      |  You shouldn't usually need to create a #[code Tokenizer] subclass.
  