Brought back memories to over a decade ago with Mathematica. It's quite easy to pattern match simple expressions like:

``` expr = foo[bar[k], baz[V]]; expr /. foo[x_, baz[y_]] :> {x, y} ```

But in real-world use cases, this paradigm quickly exposes some unhandled edge cases, or cases where the evaluation becomes prohibitively expensive. Nowadays I use TypeScript, and this has ignited some curiosity into finding out if TS does anything to optimize for this in type inference.

That’s kinda what brought unification to my attention. For my own education I’m writing a compiler for a simple ML-style language. Enjoying Pierce’s Types and Programming Languages meanwhile.