Hi,
Andrei brings in the idea of std.pattern. Seems that this module is
"stalled"; Unfortunately !
However I would like to enhance collection classes (likewise
dcollections) with a Publisher - Subscriber pattern (signal - slot, or
observer pattern) , if you prefer)
Hope the idea of enhancing collections with events become clear with the
following snippet.
---I am able to spend just a few hours a month with D programming.. in
other words, please don't kill me ;)
Untested Draft code which requires a lot of help and ,more important,
feedback from you.
struct publisherMsg(T) {
T data;
Action a;
}
mixin template Publisher(T) {
private :
enum Action = {INSERT, UPDATE, DELETE, READONLY};
//alias typeof(this) PT;
struct receiver {
Object o;
callback cb;
// opCall() or this() ?
}
receiver[] subscriber;
publisherMsg!(T) msg;
alias void delegate(ref msg) callback;
void addSubscriber(object o, callback cb) {
//subscriber ~= o;
}
void publish(T t, Action act) {
foreach (object o ; subscriber)
{
// create and send message
}
}
}
mixin template Subscriber() {
// see UndoList
}
final class Stack(T, bool observable = false ) /+ should use alias +/ {
T[] data;
static if (observable) mixin Observable!T;
void push(T t) {
publish(t, Action.INSERT)
}
T pop() {
}
bool empty() {
}
T top() {
}
size_t size() {
}
}
/// Undo list will receive every pushed or popped item (T and Action)
class UndoList(T) {
private:
T[] data;
// should be part of the subscriber mixin template.
publisherMsg!T stackMessage;
void delegate(ref stackMessage) dg;
alias Stack!(int) IntegerStack;
IntegerStack intstack = new IntegerStack;
private this() {
dg = &this.feedback;
}
public void feedback(ref stackMessage msg ) {
writefln("push or pop action");
}
}
-Bjoern
