SwiftCSP is a constraint satisfaction problem solver written in pure Swift (no Cocoa). It utilizes a simple backtracking algorithm with plans for future optimizations. At this stage of development, it's fairly slow but it includes examples of solving actual problems. It runs on both iOS and OS X.
Xcode Logger is a fast (up to *35x times faster than NSLog), very simple to use, flexible library which provides scheme-based, customizable and colorful (using the Xcode Colors plugin) NSLog replacements. *based on tests comparing NSLog vs XLog's No Header level, average operation time after 5 runs with 5000 iterations per test, per run on a MacBook Pro Retina.