const std = @import("std");
const builtin = @import("builtin");

fn foo(n: usize) usize {
    return n * 10;
}

fn makefunc(comptime func: var) @typeOf(func) {
    const TargetFnType = @typeOf(func);
    const target_fn_info = @typeInfo(TargetFnType).Fn;
    const args = target_fn_info.args;

    return struct {
        fn call(n: args[0].arg_type.?) TargetFnType.ReturnType {
            std.debug.warn("calling a function\n");
            std.debug.warn("{}\n", n);

            return func(n);
        }
    }.call;
}

const decorated = makefunc(foo);
const doubledecorated = makefunc(decorated);

pub fn main() void {

    //std.debug.warn("{}\n", decorated(10));
    std.debug.warn("{}\n", doubledecorated(10));
}