Java's new green threads are built on delimited continuations.

Delimited continuations have been implemented in the de-facto standard Haskell runtime system, the GHC runtime system [0]. The goal was to make effect systems more performant [1], but I believe that work has stalled due to the maintainer shifting priorities.

[0]: https://github.com/ghc-proposals/ghc-proposals/blob/master/p...

[1]: https://blog.poisson.chat/posts/2023-01-02-del-cont-examples...

By "it" do you mean delimited continuations? If so, my understanding is that they are the standard mode of interruption in Racket — all error-raising/handling and other continuation forms (call/cc, etc) are implemented in terms of delimited continuations because they're a more general abstraction than the older primitives. You can read about Racket's continuation model and where they're used in §10.4 of the Racket Reference [1].

[1] https://docs.racket-lang.org/reference/cont.html

The Ocaml 5 effect system is based on delimited continuations, and its new effect-based IO library, Eio, seems to be getting more and more popular all the time.

Exceptions with throw/catch are 90% of the way to delimited continuations so in a sense everyone is already using a close subset of it!

They could be useful in typical exception handling contexts where the operation could be retried. An operation involving a file read that fails due to file not being found could be body could be resumed with dummy data or data sourced from alternative locations. Lisps also like to show a REPL and allow the programmers to plug in the value themselves.

They are required for any compliant Scheme implementation.