Comment by kccqzy
1 day ago
Constrained GOTO semantics sounds a lot like delimited continuations. Indeed I think Scheme continuations are a little too powerful for regular use by having the possibility of global effect (like longjmp). Delimited continuations make the effect more local.
Delimited continuations always bounced off of me. In theory, they should be a lot like coroutines? I think, in practice, I just never really internalized all that goes into managing the current "environment" for a piece of code that is managed by the call state.
Like, I have a few partial mental models for everything that they pull together. I haven't really tried to build on that, though. Should put some time to that.
You could implement coroutines with deliminated continuations, which is probably the best way to use deliminated continuations.
Effect handlers would like to have a word.
If you'll excuse the self-post, here's a blog post on goto with delimited continuations.
https://rd.nz/2009/03/goto-in-scala.html
It uses an experimental compiler plugin for the Scala compiler. It's typesafe at compile time. At runtime unfortunately it relies on exceptions for control flow.