code: func (p *Parser) parseTokens(toks []Token) error {
  	for _, expected := range toks {
  		if tok, pos, lit := p.ScanIgnoreWhitespace(); tok != expected {
  			return newParseError(tokstr(tok, lit), []string{tokens[expected]}, pos)
  		}
  	}
  	return nil
  }
docs: // parseTokens consumes an expected sequence of tokens.