Crosscut

I was going to rule out exceptions as an option for error handling, but I'm no longer sure. Before we get into that though, let's look at how I thought that variant types and automatic lifting could address my design goals. And then, later on, why that probably won't work.

In this model, every function that can trigger an error returns a variant, with cases for its main return value and the error. But without early returns like in Rust (they don't interact well with linear types, for the same reason that effects or exceptions don't), you'd have to carry the errors through to the end of the function.

But then you'd have to deal explicitly with those variants after every function call that returns them. This could end up rather verbose, unless you invent special syntax (like do notation). And this is where automatic lifting comes in. It would allow you to just write code for the ideal case, while automatically carrying errors to the function's exit point.