> I guess only I'd disagree here that the additional assumptions are "fairly onerous" - but that's just an opinion. You may be doing work that butts into those

> I guess only I'd disagree here that the additional assumptions are "fairly onerous" - but that's just an opinion. You may be doing work that butts into those assumptions far more often than I do (which is almost never). I originally meant this mostly in the sense that it forbids a lot of values. But I do also think this is a bit of a Blub situation. There's a good class of pure data algorithms where basically everything you want to interact with is data, and if you're working in that space it's pretty great. But having spent some time in resource-typed languages, for any situation where I have to work with external resources or effects that can't be undone working in a language that doesn't have resource types and deterministic constructors really feels like a big step backwards. There are so many invariants you can't capture if you can't reason about value invalidation.