快速替换Objective-C宏 [英] Swift replacement for Objective-C macro

问题描述

我忙于用Swift重写应用程序，并希望将以下宏转换为Swift代码.

I busy rewriting an app in Swift and would like to convert the following macro to Swift code.

#define FLOG(format, ...)               NSLog(@"%@.%@ %@", [self class], NSStringFromSelector(_cmd), [NSString stringWithFormat:format, ##__VA_ARGS__])

如何将其定义为Swift函数，以便可以在任何地方用于调试日志记录目的，或者是否可以通过另一种方法来实现同一目的?

How can I define this as a Swift function such that I can use if anywhere for debug logging purposes, or is there an alternate way to achieve the same thing?

推荐答案

最简单的方法可能是利用字符串插值并使用:

The easiest way is probably to take advantage of string interpolation and use:

func FLOG(message:String, method:String = __FUNCTION__) {
    println("\(method): \(message)")
}

然后您的用法类似于:

FLOG("Illegal value: \(value)")

将方法参数默认为__FUNCTION__意味着通常将其替换为调用函数名称.您可以使用的其他自动变量包括__FILE__，__LINE__和__COLUMN__.不幸的是__PRETTY_FUNCTION__不再可用.

Having the method argument default to __FUNCTION__ means that it will normally be replaced with the calling function name. Other automatic variables that you could use include __FILE__, __LINE__ and __COLUMN__. Unfortunately __PRETTY_FUNCTION__ is no longer available.

如果您要对消息格式进行更多控制，而不是字符串插值允许，请查看

If you want more control over the formatting of the message than string interpolation allows, take a look at this question which demonstrates simplifying access to printf-style formatting in Swift, and would let you do:

FLOG("Illegal value: %x" % [value])

另请参阅来自Apple的此帖子，该地址使用__FILE__和assert

See also this post from Apple that addresses using __FILE__ and __LINE__ in assert

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