implement higher-level API on abstract

[nadako]

it should be possible with Haxe to implement a very nice OO-ish API on top of the basic defold api with zero run-time cost using abstracts. look into that.

[nadako]

another idea would be to provide macro-powered sugar for handling and sending messages (see https://forum.defold.com/t/haxe-defold/44368/8)

that begs for property sugar as well, ok now I want to design something :)

[haath]

Would this API be ok?

import defold.support.CallbackDispatch;

override function on_message<T>(self:Props, message_id:Message<T>, message:T, sender:Url)
{
    // Macro function to generate callback calls.
    CallbackDispatch.dispatchMessage(message_id, message, sender);
}

Then the callbacks could look like this:

typedef MessageOne = {
    var param1: Int;
    var param2: Vector3;
}
typefdef MessageTwo = { ... }

@:message function onMessageOne(self:Props, sender:Url, msg:MessageOne) { }
@:message function onMessage2(self:Props, sender:Url, msg:MessageTwo) { }

The message type here is deducted from the third parameter.

Another alternative would be to do it like this.

@:message(msg:MessageOne) function onMessageOne(self:Props, sender:Url, param1:Int, param2:Vector3) { }

A bit prettier, but would cause compilation errors when the message typedef is updated, all callback methods using said message would need to be updated manually.

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Then I'm also thinking we could have generated public static methods for posting messages.

public static inline function postMessageOne(url: Url, param1: Int, param2: Vector3) {
    // The message id will of course be pre-hashed somewhere.
    Msg.pos(url, hash("_TypeName_MessageOne_",
    {
        param1: param1,
        param2: param2
    })
}

Or is it better to not have statics at all, and go straight for an abstract OOP implementation?
I have sort of started doing something similar here.

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Ditto all of the above for on_input as well.