Another year has come and gone with no activity on this blog - but things will be different this year. A new domain, a new theme, but this time with more content!

The code for this post can be downloaded here.

One of the joys of Scala is actually being able to code in a much more functional style than you can in Java. But inevitably as you start down that route you start using the machinery of advanced functional programming: monads, monad transformers and their ilk.

So it’s a bit of a shock when what looks like some perfectly innocent code stack overflows in your face.

Once again, it’s been far too long since I updated this, but better late than never!

I gave my post as a talk at the recent ScalaSyd, and you can get the slides here.

As an aside, I made the somewhat hand-wavy allegation that the normal Hom-functor that we use is in some way the “right” one. I sat down to actually try to prove this, and I haven’t been able to come up with anything satisfactory. On the face of it, there’s no reason why there shouldn’t be other functors that behave the same as the Hom-functor on objects, but do something different to the arrows. So unless there’s a cunning proof that there can’t be such a functor in generality, or there’s an independent characterisation of the Hom-functor that I haven’t thought of, I’m a bit stumped.

Ideas welcome!

[epistemic status: mostly believed, high confidence]

I was putting together some readings about effective altruism, and I realised that the resources I’d picked out nicely mirror and support the stages of a prototypical argument for effective altruism.