Gregory's Server@abcdw @wingo I'm not sure it qualifies, but Section 5 of this draft describes how to add delimited computations to a language using a meta language that can express delimited continuations
https://people.rennes.inria.fr/Alan.Schmitt/papers/programming_draft.pdf
@brab Good job on the paper! but maybe it's a little too much complicated for me right now :)
I already found a few nice links on the topic of continuations, probably will share them, when learn the material.