const std = @import("std");

const warn = std.debug.warn;
const allocator = std.debug.global_allocator;

fn foo(n: u32) u32 {
    return n * 2;
}

pub fn main() !void {

    var handle = try async<allocator> slow_action();

    var mapped = try async<allocator> map(u32, u32, handle, foo);

    resume mapped;
}

async fn map(comptime T: type, comptime U: type, p: promise-> T, f: fn(T) U) U {
    var result = await p;

    return f(result);
}

async fn slow_action() u32 {
    var n: usize = 0;

    while(n < 10): (n += 1) {
        suspend;
    }

    return 1;
}