目标C-定义宏以调用方法吗? [英] Objective C - Defining macro to call a method?

问题描述

我想定义一个宏来调用以下内容，这可能吗? 我也希望它接受格式字符串.

I want to define a macro to call the following, Is this possible? I also want it to accept format string.

- (void)logString:(NSString *)string withLogLogLevel:(LogLevel)logLevel
{
   // Sav log to file
}

DLog("text");
[Logger logString:text withLogLevel:LogLevelDebug];

ILog("text");
[Logger logString:text withLogLevel:LogLevelInfo];

ELog("text");
[Logger logString:text withLogLevel:LogLevelInfo];

推荐答案

假定logString:withLogLevel:除了日志级别外还采用单个字符串参数，这应该是可能的:

Assuming that logString:withLogLevel: takes a single string parameter in addition to the log level, this should be possible:

#define DLog(x) [Logger logString:(x) withLogLevel:LogLevelDebug]

请注意macro参数周围的括号，当用复合表达式调用宏时，此功能很有用.

Note the parentheses around the macro parameter, it is useful when macros are called with composite expressions.

假设记录器使用的是NSString对象，而不是C字符串，则应使用这样的宏:

Assuming that the logger takes NSString objects, not C string, you should use the macro like this:

DLog(@"Text");

DLog(@"Text");

但是，在这种情况下，尚不清楚为什么人们会偏爱宏而不是简单的函数调用:

However, in this case it is not clear why would one prefer a macro to a simple function call:

void DLog(NSString *str) {
    [Logger logString:str withLogLevel:LogLevelDebug];
}

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