Swift:扩展print()函数的功能

Question

是否可以扩展Swift功能的功能？我想在我的程序中的每个print()函数上添加一个字符,而不必创建一个全新的函数并重命名print()的每个实例.是否可以创建一个在每个打印实例上附加'*'的扩展名？

这样做的目的是创建一种清除XCODE添加到调试器中的所有额外信息的方法.我使用print语句检查代码的不同部分的进度和成功,但XCODE在几秒钟内填写了数千行超额信息,很快就掩盖了我的具体陈述.

我想做的事:

print("Hello world!")
//Psuedo code:
Extension print(text: String) {
    let newText = "*\(text)"
    return newText
}

输出:*Hello World!

然后我将过滤星号的Xcode调试输出.我一直在手动这样做

Answer 1

您可以print从标准库中掩盖该方法:

public func print(items: Any..., separator: String = " ", terminator: String = "\n") {
    let output = items.map { "*\($0)" }.joinWithSeparator(separator)
    Swift.print(output, terminator: terminator)
}

由于原始函数位于标准库中,因此其完全限定名称为 Swift.print

Answer 2

这段代码在swift 3中为我工作

import Foundation

public func print(_ items: Any..., separator: String = " ", terminator: String = "\n") {
    let output = items.map { "\($0)" }.joined(separator: separator)
    Swift.print(output, terminator: terminator)
}

class YourViewController: UIViewController {
}

Answer 3

如果我们想用自定义覆盖所有情况，print我们应该创建新文件，例如：CustomPrint.swift然后粘贴这两个方法：

斯威夫特 5.1

First (according to ThomasHaz answer)

public func print(_ items: String..., filename: String = #file, function : String = #function, line: Int = #line, separator: String = " ", terminator: String = "\n") {
    #if DEBUG
        let pretty = "\(URL(fileURLWithPath: filename).lastPathComponent) [#\(line)] \(function)\n\t-> "
        let output = items.map { "\($0)" }.joined(separator: separator)
        Swift.print(pretty+output, terminator: terminator)
    #else
        Swift.print("RELEASE MODE")
    #endif
}

and second because the first one does't cover dictionary and array printing

public func print(_ items: Any..., separator: String = " ", terminator: String = "\n") {
    #if DEBUG
        let output = items.map { "\($0)" }.joined(separator: separator)
        Swift.print(output, terminator: terminator)
    #else
        Swift.print("RELEASE MODE")
    #endif
}

享受 ：）