nested depth 4

// Depth 4 test: start |> +1 |> +2 |> +3 |> +4 → result (10+1+2+3+4 = 20)
const std = @import("std");
~import "$std/io"

~event add_one { value: i32 }
| done { result: i32 }
~add_one = done { result: value + 1 }

~event add_two { value: i32 }
| done { result: i32 }
~add_two = done { result: value + 2 }

~event add_three { value: i32 }
| done { result: i32 }
~add_three = done { result: value + 3 }

~event add_four { value: i32 }
| done { result: i32 }
~add_four = done { result: value + 4 }

~add_one(value: 10)
| done a |> add_two(value: a.result)
    | done b |> add_three(value: b.result)
        | done c |> add_four(value: c.result)
            | done d |> std.io:print.ln("{{d.result:d}}")