objective-c - 为什么 prepareWithInvocationTarget: 特定于 NSUndoManager？

Question

比较...

NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:[performer methodSignatureForSelector:@selector(playFile:)]];
[invocation setSelector:@selector(playFile:)];
[invocation setTarget:performer];
NSString* string = [NSString stringWithString:@"reverse.wav"];
[invocation setArgument:&string atIndex:2];

...和...

NSInvocation* invocation = [[NSInvocation prepareWithTarget:performer] playFile:@"reverse.wav"];

. 为什么没有实现这样的方法？

Answer 1

事实并非如此，但不乏相同功能的第三方实现，例如为Cocoa with Love编写和创建的实现。