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@Sgeo
Created December 19, 2021 08:24
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effect focus<a>
ctl focus(a : a): a
fun vl-fst(f: a -> focus<r> b): (((a, c)) -> focus<r> (b, c))
fn(pair)
match pair
(a, c) -> (f(a), c)
fun vl-snd(f: a -> focus<r> b): (((c, a)) -> focus<r> (c, b))
fn(pair)
match pair
(c, a) -> (c, f(a))
// Allowing focus in the modifier might be a problem. Figure out how to get rid of it?
fun over(optic: ((a) -> focus<r> b) -> ((s) -> focus<r> t), modifier: (a -> b), target: s): t
with fun focus(a)
a
val large_modifier = optic(modifier)
large_modifier(target)
fun over-elim(a: a, action: (a -> focus<r> b)): b
with fun focus(a)
a
action(a)
fun get-elim(a: a, action: (a -> focus<r> b)): exn r
with handler {
brk focus(a)
a
return(a)
throw("No focus!")
}
action(a)
// Can't figure out how to type this!
// fun get(s: s, optic: ((a) -> focus<a> a) -> ((s) -> focus<b> a)): exn b
// get-elim(s, optic(focus))
fun main() : console ()
println("Hello, world!")
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