anchor.diff:          span.merge(is_stop=True) # merge (and mark it as a stop word, just in case)
           span.set_flag(BAD_HTML_FLAG, True) # set BAD_HTML_FLAG
   
  +    matcher.add('BAD_HTML', on_match=merge_and_flag,
  +                [{'ORTH': '&lt;'}, {'LOWER': 'br'}, {'ORTH': '&gt;'}],
  +                [{'ORTH': '&lt;'}, {'LOWER': 'br/'}, {'ORTH': '&gt;'}])
  +
   +aside("Tip: Visualizing matches")
       |  When working with entities, you can use #[+api("displacy") displaCy]
       |  to quickly generate a NER visualization from your updated #[code Doc],
  
positive.code:     |  function #[code merge_and_flag]:
  
  +code.
      matcher.add('BAD_HTML', on_match=merge_and_flag,
                  [{'ORTH': '&lt;'}, {'LOWER': 'br'}, {'ORTH': '&gt;'}],
                  [{'ORTH': '&lt;'}, {'LOWER': 'br/'}, {'ORTH': '&gt;'}])
  
      # Add a new custom flag to the vocab, which is always False by default.
      # BAD_HTML_FLAG will be the flag ID, which we can use to set it to True on the span.
      BAD_HTML_FLAG = doc.vocab.add_flag(lambda text: False)
  
negative.code:         +cell
              |  A list of #[code (match_id, start, end)] tuples, describing the
              |  matches. A match tuple describes a span #[code doc[start:end]].
  
  +h(2, "quantifiers") Using operators and quantifiers
  
  p
      |  The matcher also lets you use quantifiers, specified as the #[code 'OP']
      |  key. Quantifiers let you define sequences of tokens to be mached, e.g.
      |  one or more punctuation marks, or specify optional tokens. Note that there
      |  are no nested or scoped quantifiers – instead, you can build those
      |  behaviours with #[code on_match] callbacks.
  
  +aside("Problems with quantifiers")
      |  Using quantifiers may lead to unexpected results when matching
      |  variable-length patterns, for example if the next token would also be
      |  matched by the previous token. This problem should be resolved in a future
      |  release. For more information, see
      |  #[+a(gh("spaCy") + "/issues/864") this issue].
  
  +table([ "OP", "Description", "Example"])
      +row
          +cell #[code !]
          +cell match exactly 0 times
  