code: function parser(tokens) {
    // add Close token before each Else
    const toks = tokens.reduce((prev, tok) => {
      if (tok.tokenType === 'Else') {
        return [...prev, new Close(), tok];
      }
  
      return [...prev, tok];
    }, []);
  
    const [body] = parse(toks, '', 1);
    return body;
  }
docs: Parse an array of tokens into a syntax tree
  @param {object[]} tokens
  @returns {object}