APPropriate Behaviour, the book on things programmers do that aren’t programming, is now complete! The final chapter – a philosophy of software making – has been added, concluding the book. Just because it’s complete, doesn’t mean it’s finished: as my understanding of what we do develops I’ll probably want to correct things, or add new [...]
One of the interesting aspects of Smalltalk and similar languages including Objective-C and Ruby is that while the object model exposes a hierarchy of classes, consumers of objects in these environments are free to ignore the position of the object in that hierarchy. The hierarchy can be thought of as a convenience: on the one [...]
Introduction This post explores the pros and the cons of following the design rule “Objects responsible for collections of other objects should expose an interface to the collection, not the collection itself”. Examples and other technical discussion is in Objective-C, assuming Foundation classes and idioms. Example Problem Imagine you were building Core Data today. You [...]
I’m really far behind on podcasts. I have a long commute, and listen to one audiobook every month, filling the slack time with a selection of podcasts. It happens that between two really long books (Cryptonomicon by Neal Stephenson and The Three Musketeers by Alexandre Dumas, both of which I’d recommend) and quite a few [...]
What? A thing I made has just been open-sourced by my employers at Agant: the AGTTwoDimensionalDictionary works a bit like a normal dictionary, except that the keys are CGPoints meaning we can find all the objects within a given rectangle. Why? A lot of time on developing Discworld: The Ankh-Morpork Map was spent on performance [...]
In her keynote speech at QCon London 2013 on The Power of Abstraction, Barbara Liskov referred to several papers contemporary with her work on abstract data types. I’ve collected these references and found links to free copies of the articles where available. Dijkstra 1968 Go To statement considered harmful Wirth 1971 Program development by stepwise [...]
…every problem looks like it can be solved by configuring a different nail. We have an obsession with tools in the software industry. We’ve built tools for building software, tools for testing software, tools for recording how the software is broken, tools for recording when we fixed software. Tools for migrating data from the no-longer-cool [...]
A bit of a repeated theme in the construction of APPropriate Behaviour has been that I’ve tried to position certain terms or concepts in their historical context, and found it difficult, or impossible to do so with sufficient rigour. There’s an extent to which I don’t want the book to become historiographical so have avoided [...]
Wherever a book on writing software describes the 1968 NATO conference in Garmisch on Software Engineering, consider whether the clarity of the argument can be improved by adding the following parenthetical clause: […], a straw man version of an otherwise real conference that took place in 1968, […] Usually it can. The proceedings of the [...]
There’s an old trope used in discussions of Mac and iOS developers, that says they’re too inward-looking. They only think about software in ways that have been “blessed” by Apple, their platform vendor. I’m pretty sure that I’ve used this meme myself though couldn’t find an example in a short Bing for the topic. It’s [...]
