Comment by josephg

In typescript I typed my text editing operations like this:

    type Operation = {type: “insert”, …} | {type: “delete”, …} | …;

It’s trivial to switch based on the type field. And when you do, typescript gives you full type checking for that specific variant. It’s not as efficient at runtime as C, but it’s very clean code.

Go doesn’t have any equivalent to this. Nor does go support tagged unions - which is what I used in C. The most idiomatic approach I could think of in Go was to use interface {} and polymorphism. But that was more verbose (~50% more lines of code) and more error prone. And it’s much harder to read - instead of simply branching based on the operation type, I implemented a virtual method for all my different variants and called it. But that spread my logic all over the place.

If I did it again I’d consider just making a struct in go with the superset of all the fields across all my variants. Still ugly, but maybe it would be better than dynamic dispatch? I dunno.

I wish I still had the go code I wrote. The C, rust, swift and typescript variants are kicking around on my github somewhere. If you want a poke at the code, I can find them when I’m at my desk.