I have been using Applescript for over 14 years to develop scripts, and as XCode later integrated Applescript Studio and Applescript Objective-C, I have grown scripts from single-use and simple stand-alone files to fully developed applications. I learned Objective-C/Cocoa and have been using those higher performance and lower level tools to create even better applications with native controls, multiple objects/classes, and including third party frameworks for data manipulation (for example ODBCKit, which I had the original developer extend and patch as I implemented it in Ad Template Maker, and Sparkle for automatic application updates). I have been using Cornerstone for Subversion code versioning and commenting, as I had often been asked to branch applications to have unique versions or features for various departments.
I have built several applications and have sold them via the Mac App Store, and have experience submitting and managing via the MAS and iTunesConnect.