#ifdef replacement in the Swift language

Question

In C/C++/Objective C you can define a macro using compiler preprocessors. Moreover, you can include/exclude some parts of code using compiler preprocessors.

Answer 1

In Swift projects created with Xcode Version 9.4.1, Swift 4.1

#if DEBUG
#endif

works by default because in the Preprocessor Macros DEBUG=1 has already been set by Xcode.

So you can use #if DEBUG "out of box".

By the way, how to use the condition compilation blocks in general is written in Apple's book The Swift Programming Language 4.1 (the section Compiler Control Statements) and how to write the compile flags and what is counterpart of the C macros in Swift is written in another Apple's book Using Swift with Cocoa and Objective C (in the section Preprocessor Directives)

Hope in future Apple will write the more detailed contents and the indexes for their books.