code: func lexBlockComment(l *lexer) stateFn {
  	var star = false
  	for {
  		switch l.next() {
  		case eof:
  			return l.errorf("unclosed block comment")
  		case '*':
  			star = true
  			continue
  		case '/':
  			if star {
  				l.emit(itemComment)
  				return lexText
  			}
  		}
  		star = false
  	}
  }
docs: // "/*" has just been read