09. Word and Line Calculations i

相关链接：
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/AttributedStrings/Tasks/WordCalcAttrStrings.html#//apple_ref/doc/uid/20000165-BBCFEHGF

The Application Kit’s extensions to NSAttributedString support the typical behavior of text editors in selecting a word on a double-click with the `=doubleClickAtIndex: method, and finds word breaks with nextWordFromIndex:forward:. It also calculates line breaks with the lineBreakBeforeIndex:withinRange: method.

• Application Kit对NSAttributedString的扩展支持文本编辑器在使用`= doubleClickAtIndex：方法双击时选择单词的典型行为，并使用nextWordFromIndex：forward：查找单词分隔符。 它还使用lineBreakBeforeIndex：withinRange：方法计算换行符。