Well on my way to becoming comfortable with Objective-C and Cocoa, I came across the need to create two versions of an app I was working on – one a “Lite,” and the other a full version.
Branch merging scares me
Like any good developer, I use source control management to keep tabs on my development cycles. This time, being no different than any other, I dutifully created a new branch for a lite version of my application once I completed the critical features milestone. Being one who doesn’t have a lot of use for branching in most projects, I was reluctant because (be honest here) the notion of merging back and forth between the lite and the full branches was a painful one.
Ok, I know – merging shouldn’t be that big of a deal, but what about this scenario? I’m adding some features to the full version that I decide I want to port back to the lite. Auto merging isn’t going to work (we can give the lite app all the same features of big brother), but neither am I so keen on going line-by-line every time I make a change. Cry me a river, right? Well, no. Actually, the solution is easier than that.
Enter: Compiler flags
I don’t know when I first learned about it – it could have been in my early programming days when I was learning about C – but I’ve always had ideas about compiler flags in the back of my head… very dim ideas. Look through Cocoa demo apps (check your Cocoa docs) and you’ll see several that have lines of code that seem to point to something specific:
#if defined(LITE_VERSION)
//do something here
#endif
That’s a compiler flag. That’s the key to getting your lite version separated from the full version at compile time (or runtime, or whatever, depending on your need). Using those compile flags you can separate specific portions of code for one version of your app to another.
I’ll save you the dirty details of how you do this. Instead, head over to Junda Ong’s blog.