CODEWITHSUNDEEP
iosobjective-cxcodeswiftc-preprocessor
Vee
Vee

Reputation: 1841

Swift: Using Preprocessor Macros

I've created a .swift file that's mixed in with an Obj-C codebase and am wondering what the best way to set constants that are dependent on preprocessed flags for specific targets. Here's how I set constants for each target:

For "Target A", Under "Build Settings" -> "Swift Compiler - Custom Flags" -> Expand "Other Swift Flags" to reveal the following

Debug: -DDEBUG -DTARGET_A

Release: - DPRODUCTION -DTARGET_A

For "Target B", Under "Build Settings" -> "Swift Compiler - Custom Flags" -> Expand "Other Swift Flags"

Debug: -DDEBUG -DTARGET_B

Release: - DPRODUCTION -DTARGET_B

NotificationsHub.swift

#if TARGET_A
    #if PRODUCTION
        let HUBNAME = "hub1"
        let HUBLISTENACCESS = "Endpoint=endpoint1"
    #elseif DEBUG
        let HUBNAME = "hub2"
        let HUBLISTENACCESS = "Endpoint=endpoint2"
    #endif
#elseif TARGET_B
    #if PRODUCTION
        let HUBNAME = "hub3"
        let HUBLISTENACCESS = "Endpoint=endpoint3"
    #elseif DEBUG
        let HUBNAME = "hub4"
        let HUBLISTENACCESS = "Endpoint=endpoint4"
    #endif
#endif

class NotificationsHub: NSObject
{
    ...
    let hubName = HUBNAME
    let hubListenAccess = HUBLISTENACCESS
    ...
}

I don't like the ginormous nested if statement that precedes the class definition nor do I like setting constants outside of the class (are these global constants???) and would prefer to be able to specify each hubName and hubListenAccess in the project settings somewhere. In Obj-C, it's possible to specify values under "Build Settings" -> "Apple LLVM 7.0 Preprocessing" -> Expand "Preprocessor Macros", but don't know how I can do this in Swift.

Upvotes: 2

Views: 3877

Answers (1)

Atul
Atul

Reputation: 201

With XCode 8 we could use the Active Compilation Conditions to add the MACRO without the -D prefix

Upvotes: 2

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