Paul Chiusano

Functional programming, UX, tech, econ


Consulting services

I offer Scala and FP consulting services. If you're interested in working together, please contact me.

About my book

My book, Functional Programming in Scala, uses Scala as a vehicle for teaching FP. Read what people are saying about it.

Popular links

Unison: a next-gen programming platform the worldwide elastic computer (coming soon)
Type systems and UX: an example
CSS is unnecessary

Unison update 5: a better spreadsheet

Here’s a video of the latest progress. In this video, I create the term view reactive (1 + 1), which displays in the editor as 2. This might not seem like much, but the ability to define reactive views like this is the first step in allowing Unison panels to be used much like a spreadsheet, where the user fills in values and other parts of the panel are updated in response. There’s also a few other things shown which I’ll talk through below:


Unison update 4: more editor interactions

Here’s a video of the latest progress. Watch me write the expression 1 + 1, then evaluate it!! Further explanation below.


Keep your data types dumb, layer on properties after the fact

When programming in a language with a nice type system, you often have the option of defining ‘smart’ data types which bake some invariant in as an index of the data type. But sometimes, it can be better to keep your data types dumb, and layer on invariants after the fact. The lesson generalizes, but I’ll show an example—well-formed lambda calculus terms:


Unison update 3: connecting the editor to the node (continued)

I didn’t get a chance to put together a post on Friday, but I made some decent progress. Here’s a short recording of an editing session:


Unison update 2: connecting the editor to the node

As I mentioned in week 0, the Unison node is written in Haskell and has an implementation of the Unison language, its typechecker, and any primitive functions. It exposes an API over HTTP. Last week, I worked on some of the Unison editor interactions, but I was working somewhat in a vaccum since the editor wasn’t yet connected to the Unison node. I spent this week actually getting the editor and the node talking to each other, and refining the node API a bit in the process.