The main limitation at the moment is that we only support a handful of Web APIs (e.g. `fetch`, `URL`, etc.) and NodeJS APIs (e.g. `readFile`), as well as QuickJS's built-in ES2020 APIs, so if you try to run an existing app you may find it needs a Web API we don't yet support. If so, please feel free to open an issue on the `spin-js-sdk` repo.
This resembles ascending a rope using prusiks, which is a lot of fun if you haven't tried it. Great to see a variation the helps people with limited mobility to get around unassisted.
I've been making my way through this book for the past few weeks; just started Chapter 20. I tried reading Harper's Practical Foundations for Programming Languages first, but it was too abstract for me, so I switched to TaPL.
What I like most about Pierce's book is that he introduces each concept with a formal, abstract definition, complete with proofs of correctness, but also follows that up with a concrete implementation in OCaml. The latter is very easy to follow if you've had some experience with the ML family of languages. I sometimes find myself skipping ahead to the OCaml version when I get lost in the math syntax, which for me is less familiar. I'm planning to come back to Harper's book later, but Pierce's book is the perfect fit for where I am now.
My only criticism is that some parts are very dated given it hasn't been updated in almost 20 years. In particular, the version of Java he discusses throughout the book (pre-generics, pre-type-inference) bears little resemblance to the modern one. And since 2002 we've seen affine types (e.g. Rust) start to have mainstream influence, among other things.
In case it's helpful, I'm compiling a list of resources as I learn type systems, logic, category theory, etc.: