In the GIS (Geographic Information Systems) industry, ESRI Shapefile is well established and used to exchange data despite some limitations. As Dale Lutz (co-founder of Safe Software) mentionned it, the # 1 overall translation that seems to be done by FME (Feature Manipulation Engine) is surprisingly Shapefile to Shapefile! The ESRI Shapefile Technical Description is since july 1998 available.
The development layer of Mac OS X is made up by Cocoa, an Apple collection frameworks which follows the MVC (Model-View-Controller) pattern. More about Cocoa:
Built with Xcode 5.0 (Mac OS X IDE) under Mountain Lion, the Cocoa Shapefile Viewer project demonstrates some interesting features like opening by dragging file, applying transluency or saving as TIFF or PDF having just to write one or two lines of Objective-C code. Link for binary only and UML diagram.