It's only legal for each `now` to be consumed by at-most one `at` form, so at that point you'd just be re-implementing the "timeline" and "instant" system from mariposa. The need to wrap the program in a form and the management of `now` "values" has me pondering the implications of IanTheHenry's macaroni[1] system, which (like the CSS :has operator) allow macros to climb up into manipulations of their parent forms-- the `now` macro could effectively wrap every remaining form in the program with a new context that augments eg. the closure of `at`. But indeed, perhaps a problem to not become too invested in :p
uh, case in point, that hypothetical closure would have some difficulty crossing module boundries (and that's assuming it gets away with re-writing top-level define forms), but still nothing technically incomputable, just supremely ill-advised and still closer to a reimplimentation of mariposa's semantics than a truely native concept emerging out of the continuations system
1: https://github.com/ianthehenry/macaroni