In writing my first iOS app, I found myself reaching out in a few areas of self-discovery regarding the Cocoa Touch framework and what it's capable of, especially in how it compares to Ruby and it's standard library (which is what I've been used to for the past few years of my life). I've grown to love Ruby mixins and monkey-patching, and was delighted to learn that Objective-C has something quite similar: categories. ClassName+CategoryName.{h,m}
is all you need, and you can define new class/static and instance methods on an Objective-C class.
One of my other strong preferences is for the Markdown format, and thus I snagged one of the more popular C-based implementations of Markdown (named [Sundown][sun]) and wrote a category around UIWebView for effortlessly displaying a parsed file. This was all made possible in the first place by [an awesome post on Stack Overflow][sta] on using Sundown with Objective-C.
//
// UIWebView+Markdown.h
//
#import <UIKit/UIKit.h>