Arnaud Spiwack

This is important dl.acm.org/doi/10.1145/... . For instance, when you have a linear Int# in Haskell, it's the same as having an unrestricted Int#. You want the type system to understand that, that's what the authors call mode crossing.

Something I realised while working on sheaves (because it turns out to be relevant) is that the multicategorical definition of coproduct is stronger than the categorical one. Because in the multi case, the branches have access to the context. In the cat case they don't.

Hom(A+B, X) ≃ Hom(A,X)×Hom(B,X) vs Hom((Γ,A+B), X) ≃ Hom((Γ,A), X)×Hom((Γ,B), X) (assuming symmetry for simplicity)

In June, Ocaml 5.5 was released ocaml.org/changelog/20... , whose headline change is module-dependent functions (aka modular explicits). The Ocaml mailing list is no longer online, but I found in my emails me from May 2012, trying (and failing) to garner support for this feature.

At the time it didn't have a name. There was no paper. And it got basically no interest at all. I'm really happy now. I've been looking forward to this moment for almost 15 years.

I noticed something the other day. If you have a monoidal category, and a subset P of objects, then arrows from arbitrary objects to objects of P form a multicategory. We'll say that this is a category of context and P are pure objects.

From a PLT perspective, this is a friendlier re-analysis of the contextuals CCC bsky.app/profile/aspi... . See also Shulman's multicategorical logic tutorial mikeshulman.github.io/catlog/catlo... .

I noticed something the other day. If you have a monoidal category, and a subset P of objects, then arrows from arbitrary objects to objects of P form a multicategory. We'll say that this is a category of context and P are pure objects.

The nice thing is that ordinary categorical structure on the category of context gives rise to structure on the multicategory (aka generalised multicategories). E.g. a symmetric monoidal category of context gives rise to symmetric multicategories.

I noticed something the other day. If you have a monoidal category, and a subset P of objects, then arrows from arbitrary objects to objects of P form a multicategory. We'll say that this is a category of context and P are pure objects.

In fact, all ordinary multicategory are of this form. Let M be a multicategory. Take contexts to be lists of objects of M, and context arrows to be lists of parallel arrows in the obvious way. Taking pure objects to be the singletons recovers M.

I noticed something the other day. If you have a monoidal category, and a subset P of objects, then arrows from arbitrary objects to objects of P form a multicategory. We'll say that this is a category of context and P are pure objects.

The Ocarina of Time remake is right around the corner. And the marketing is all around me. I wanted to take the opportunity to clarify a position: it's going to be a good game. Ocarina of Time is the most beloved video game of all times, and this is, for the most part, the same game.

Some bits are going to be a little better, some are going to be a bit worse. But it's going to be good. Even if I'm not a fan of… the choices.

I don't think this works super well for arbitrary relation equipments. First let's say that F is a functor if both: it maps arrows to arrows, and it maps composite relations R(f,g) to F(R)(F(f),F(g)).

Then, let f:A->B (and B double as the identity relation at B), we have F(B)(1,F(f)) = F(B(1,f)) ⊆ G(B(1,f))(α,α) = B(G)(α,G(f)∘α). This isn't enough to prove that α is natural. But if the target category of F and G is set, then companions are graphs.

I was walking in a book store today, and I saw a manga series has obviously been drawn by the same author as Full Metal Alchemist. The style was unmistakable. Getting closer I recognised the character: it's Daemons of the Shadow Realm. An anime I watched just a few weeks ago.

But then, I hadn't recognised the style at all. The anime looks just completely generic (it's quite compelling though). Another anime I watched recently is Witch Hat Atelier. Here again a rather generic looking but compelling anime. Then I saw what the manga looked like.

I rather like this, it's quite clever people.cs.nott.ac.uk/pszgmh/flow-... . It was already decently documented that borrowing can be thought as a lens operation. What Wilshaw and Hutton add is that you have to consider how those lenses are composed.

Now, I don't know how practical this is. Everything appears to be desugared as a lens, this would introduce a lot of overhead, hopefully this can be optimised away in most cases. Also, I've come to distrust state-passing type system. They cause too many problems.

I rather like this, it's quite clever people.cs.nott.ac.uk/pszgmh/flow-... . It was already decently documented that borrowing can be thought as a lens operation. What Wilshaw and Hutton add is that you have to consider how those lenses are composed.

Another remarkable feature is that this eventually desugars to an ordinary linear λ-calculus, showing the relevance of borrowing-like features without having to introduce notions of ownership.

I rather like this, it's quite clever people.cs.nott.ac.uk/pszgmh/flow-... . It was already decently documented that borrowing can be thought as a lens operation. What Wilshaw and Hutton add is that you have to consider how those lenses are composed.

I quite like the idea in this talk (I couldn't find a matching paper) www.youtube.com/watch?v=5bHR... to distinguish type □ A (computes a value of type A) and type ◇ A (computes a value of type A OR has a type error).

It's game day apparently. I want to shout out the Mermaid's Mask. It's the third Detective Grimoire game (I haven't played the two first ones).

It's well worth playing: the presentation is truly excellent. The visual design is good, the animation is good, the writing is excellent, the VOICE ACTING is excellent. If you know me, you probably know that I constantly complain about voice acting in game. 3/4

It's game day apparently. I want to shout out the Mermaid's Mask. It's the third Detective Grimoire game (I haven't played the two first ones).

The first time I played Worldless, I didn't do anywhere near a 100% run. Aside: if you're intro metroidvanias at all, this game is a must play: it's a very unique and delightful take on the genre (and did I mention gorgeous?).

But when I launched the game again, the game crashed before even reaching the title screen. So I can't even attempt the superboss which is behind the platforming challenge (and in fact, the only way to play the game at all is to erase my entire save data).

The first time I played Worldless, I didn't do anywhere near a 100% run. Aside: if you're intro metroidvanias at all, this game is a must play: it's a very unique and delightful take on the genre (and did I mention gorgeous?).

I eventually figured it out: the game had started crashing every time it would give me an achievement (and I wouldn't get the achievement, but the game was saved, so I could continue from there).

The first time I played Worldless, I didn't do anywhere near a 100% run. Aside: if you're intro metroidvanias at all, this game is a must play: it's a very unique and delightful take on the genre (and did I mention gorgeous?).

When we came up with Topiary our goals weren't too ambitious: make it cheap to write decent formatters for new languages, reducing the amount of stuff you have to maintain.