可可 - 切换一个BOOL不重复的名字 [英] Cocoa -- toggling a BOOL without repeating its name
问题描述
如果一个BOOL有一个很好的简称，它是很容易写：
If a BOOL has a nice short name, it's easy enough to write:
myBOOL = !myBOOL;
但是，如果BOOL有很长的名字？
But what if the BOOL has a long name?
objectWithLongishName.memberWithLongishName.submember.myBOOL = !(objectWithLongishName.memberWithLongishName.submember.myBOOL);
。 。 。看起来不那么pretty。
. . . does not look so pretty.
我不知道是否有来切换BOOL无需输入其名称两次简单的方法？
I'm wondering if there is an easy way to toggle the BOOL without entering its name twice?
推荐答案
下面是另一个：
MyBooleanYaddaYadda ^= YES;
这是有点脆 - 这将打破传统的C code这意味着任何非零的整数计算为真。不过话又说回来，这样将苹果框架code - 我遇到的情况在哪里可可非零，非一INT，当作为BOOL过去了，不会造成同样的效果传递YES
This is kinda brittle - it will break on legacy C code that implies that any nonzero integer evaluates to true. But then again, so will Apple framework code - I encountered cases in Cocoa where a nonzero, non-one int, when passed as a BOOL, would not cause the same effect as passing a YES.
但是，它不依赖的是位模式 - 只在NO是0.这是pretty多一个给定的，考虑到中c间$ P $点整数作为逻辑值。此外，它不承担BOOL的实际数据类型（这对可可符号字符，顺便说一句）。
However, it does not rely on the bit pattern of YES - only on NO being 0. Which is pretty much a given, considering the way C interprets integers as logical values. Also, it does not assume the actual datatype of BOOL (which on Cocoa is signed char, by the way).
是对可可的位模式为1。但是，这不是一个普遍的惯例。在某些平台上没有内置布尔数据类型，充当一个逻辑TRUE整型常量是 1 - 全1。这是为0xFFFFFFFF如果跨preTED为无符号。这种编码具有模糊优点bitwize NOT（在〜中C运算符）等效于逻辑NOT（在C！运算符）。即，〜0xFFFFFFFF的是0，也就是即〜TRUE为FALSE。如果真被定义为1不会这样的。
The bit pattern of YES on Cocoa is 1. But that's not a universal convention. On some platforms with no built-in boolean datatype, the integer constant that serves as a logical TRUE is -1 - all one bits. That's 0xFFFFFFFF if interpreted as unsigned. This coding has a vague advantage that bitwize NOT (the ~ operator in C ) is equivalent to logical NOT (the ! operator in C). That is, ~0xFFFFFFFF is 0, i. e. ~TRUE is FALSE. Doesn't work that way if TRUE is defined as 1.
这篇关于可可 - 切换一个BOOL不重复的名字的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
