I’m an avid reader of the blog of Wil Shipley, a man in the business of writing great apps for OS X. His running code improvment series, Pimp My Code, takes submissions from readers who think their code needs refactoring. Then Shipley refactors them, explaining the whys and hows along the way. The submissions are small (never more than 75-100 lines), but in rewriting them Shipley always happens upon specific, useful programming tips. I don’t know the first thing about Objective-C, but I find the series fascinating and instructive.
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