libgx

• A C++11 library like Golang

Golang	C++	Desc
error	error	error
nil	nil	nullptr
func foo() (int, string, error) { return 0,"s", errors.New(“err”) }	R<int, string, error> foo() { return {0, "s", errors::New("err")}; }	return multi-values
n, s, err := foo()	C++11: AUTO_R(n, s, err, foo()); C++17: auto [n, s, err] = foo();	get multi-values
*T	Ref<T>	Ret<T> == std::shared_ptr<T>
[]T	slice<T>	slice
[]*T	slice<Ref<T>>	slice
[]byte	bytez<>	byte slice
[]string	stringz<>	string slice
B[m:n], B[m:], B[:n], B[:]	B(m, n), B(m), B(0,n), B(0,-1)	slice
len(a), cap(a)	len(a), cap(a)	len, cap
make([]T, len, cap)	make<T>(len, cap)	make
copy(a, b)	copy(a, b)	copy
append(a, b)	append(a, b)	append
io.Copy(writer, reader)	io::Copy(writer, reader)	io Reader Writer
defer expr	DEFER(expr)	defer
map[K]V	map<K, V>	map
chan T	chan<T>	chan
<more> ...	...	...
-	-	-
net.Conn, net.PacketConn	net::Conn, net::PacketConn	net lib
strings.Index	strings::Index	strings lib
<more> ...	...	...
-	-	-
print, println, panic	print, println, panic	func
-	-	-

// Golang

type CallbackFn func(n int) ([]byte, error)

func foo(fn CallbackFn) (int, string, error) {
    b, err := fn(100)
    if err != nil {
        return 0, "a", err
    }

    c := append(b[:2], 'c')
    println("c =", c)

    var wg sync.WaitGroup
    wg.Add(1)

    go func() {
        defer wg.Done()
        for {
            println("hello", 100)
            time.Sleep(time.Second * 5)
            break
        }
    }()

    wg.Wait()

    return 1, "b", errors.New("err")
}

// C++

using CallbackFn = func<R<bytez<>, error>(int)>;

R<int, string, error> foo(const CallbackFn& fn)  {
    // auto [b, err] = fn(100); // >= C++17
    AUTO_R(b, err, fn(100));    // C++11/14
    if (err != nil) {
        return {0, "a", err};
    }

    auto c = append(b(0, 2), 'c');
    println("c =", c);

    sync::WaitGroup wg;
    wg.Add(1);

    gx::go([&] {
        DEFER(wg.Done());
        for (;;) {
            println("hello", 100);
            time::Sleep(time::Second * 5);
            break;
        }
    });

    wg.Wait();

    return {1, "b", errors::New("err")};
}