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{ Category Archives } OOP

Book update: OOP the Easy Way

Obejct-Oriented Programming the Easy Way gets ever closer, as the first part (of three) is now substantively complete. If you have been holding off from buying the book, now would be a great opportunity to jump in, as a whole part of the book’s argument is now laid out. As ever, your feedback is welcome, […]

OOP the Easy Way

It’s still very much a work in progress, but OOP the Easy Way is now available to purchase from Leanpub (a free sample is also available from the book’s Leanpub page). Following the theme of my conference talks and blog posts over the last few years, OOP the Easy Way starts with an Antithesis, examining […]

Or maybe, because we want to

How (and Why) Developers Use the Dynamic Features of Programming Languages: The Case of Smalltalk is an interesting analysis of the reality of dynamic programming in Smalltalk (Squeak and Pharo, really). Taking the 1,000 largest projects on SqueakSource, the authors quantitatively examine the use of dynamic features in projects and qualitatively consider why they were […]

Rethinking Object-Oriented Design figures

My iPad-drawn graphics in Rethinking OOD at App Builders 2018 were not very good, so here are the ink-and-paper versions. Please have them to hand when viewing the talk (which is the first of a two-parter, though I haven’t pitched part two anywhere yet).

Inheritance still doesn’t make any sense

Some ideas based on feedback to the Why inheritance never made any sense: Feedback: Subtypes are necessary The only one of these that is practically workable is behaviour inheritance <=> subtype inheritance: I’m sorry that you were exposed to Java at such an impressionable age. The compilers of languages like Java enable subclass = subtype, […]

Why inheritance never made any sense

There are three different types of inheritance going on. Ontological inheritance is about specialisation: this thing is a specific variety of that thing (a football is a sphere and it has this radius) Abstract data type inheritance is about substitution: this thing behaves in all the ways that thing does and has this behaviour (this […]

In defense of `id`

Something you can’t see about my dotSwift talk on OOP in FP in Swift is that to make the conference more interesting while the AV was set up for the next speaker, Daniel Steinberg invited me over to a side table for a question and answer session. He had some great questions and I had […]

On Inheritance

I recently had the chance to give my OOP-in-FP-in-Swift talk again in NSLondon, and was asked how to build inheritance in that object system. It’s a great question, I gave what I hope was a good answer, and it’s worth some more thought and a more coherent response. Firstly, let’s look at the type signature […]

machoo – Object-Oriented Programming in Object-Oriented Programming in the GNU HURD

For the last few weeks, my when-I-get-to-it project has been machoo, which is sort of an object-oriented system on the HURD but mostly an excuse to learn about how Mach messaging works. I decided to build a Smalltalk-style “give me any old selector, and I’ll do something with it” messaging system on Mach, which is […]

An update on the HURD project

Last time, on Structure and Interpretation of Computer Programmers, I was building an object-oriented programming system on top of the HURD, and had realised that I needed to use its trivfs library for a sender to be able to discover an object to send messages to. I got it working very quickly, but ended up […]