On Fri, Apr 28, 2017 at 11:50:48AM +0200, Denis Kudriashov wrote:
In fact they are not adapters. They are factories which creates backend views (morphs). And now there are completely no logic behind them: every adapter just passes state received from model to view instance.
This depends heavily on what the respective APIs provide. In TabAdapter I connect SpecTab and MorphicTab directly, so it no longer lives during runtime. In LabelAdapter the emphasis is being transcoded from symbol to random numbers (so this is not simple delegation) In MenuItemAdapter you can see much more behavior. So the naming is appropriate, but it is overall poorly connected.
Now Spec allows very restricted relationship between model and view. We can only have single kind of view per model (MorphicAdapterBindings defines this relation). There is no way to use different kind of views for same model in single application.
As I've shown in my previous answer this is not the case. The connection is done via the class-side spec method where you can specify any class at all; MorphicAdapterBindings is just a convenience, you can put there whatever you want. Likewise when you are composing widgets, you can specify what layout to use, something like (don't remember the precise naming out of my head) ^ SpecRowLayout composed add: #textModel withSpec: #cocoaSpec
But it not works.
I've used it several times so it does work, if you had troubles then maybe it doesn't work with all models.
Now you can imaging that if we always use same view class for same model class then we can directly ask model to instantiate view. Message can be backend specific like createMorphicView: and we need hierarchy of backends here which will choose appropriate message.
Which is exactly what we do not want, to directly bind model to the view; but I feel I am missing your point, can you rephrase it please?
P.S. Every time I read word model in Spec I feel something bad. It should be named to presenter. But it is quite difficult due to compatibility. And I am not sure that others agree with this.
When you go the the internals, then depending on the context spec can mean: spec layout, adapter, spec model; and in some parts all contexts overlap, so it's fun to read. :) Now Pharo 7 will have new SpecInterpreter (it took me two weeks and I've created two extra tools to understand the old one and there are still some special exceptions), so then we can rethink the way it is done. Peter
2017-04-28 0:04 GMT+02:00 Peter Uhnak <i.uhnak@gmail.com>:
Hi Rob,
I guess the best resource at the moment is to just look at existing adapters.
But here are some thoughts to get you started:
(Spec) ComposableModel has as its widget (Spec) Adapter Adapter has as its widget the actual visual component, which currently means Morphic.
The simplest example: LabelModel
1. model to adapter
LabelModel is adapted by MorphicLabelAdapter:
you can see on the class side in method `defaultSpec`. There is only `LabelAdapter` there because there is some extra mapping for some classes, but you can specify directly the class of the Adapter, so the following would work just as well:
LabelModel class>>defaultSpec <spec>
^ #(MorphicLabelAdapter adapt: #(model))
LabelModel -> LabelAdapter direct event propagation (pushing changes)
in Model world you can call changed:with: to execute code on the Adapter, e.g.
self changed: #emphasis: with: {emphasis}
which in turn will call the #emphasis: method on the LabelAdapter.
LabelModel -> LabelAdapter events (pulling changes)
preferred alternative is to do the opposite; properties of models are often held in ValueHolders, which can be observed on ValueChange, so the Adapter can register to event change and react on itself;
you can see this best in MorphicTabAdapter (but you will see that TabAdapter looks a bit different from the rest, because I was experimenting with cleaning up Adapters...)
2. adapter to morphic
Every adapter implements #buildWidget method that returns a Morphic Object. Typically the adapter registers itself as the model of the adapter (so adapter's model is Spec, and Morphic's model is the adapter). This depends a lot on the API of morphic. (in TabAdapter I'm overriding adapt: so there's no buildWidget, and it is in #buildWidgetWith:).
It is all kinds of messy, but if you have other widgets then it will be a good test how well Spec can handle it... or rather we'll see how it can be improved...
Peter
On Thu, Apr 27, 2017 at 05:10:39PM -0400, Rob Rothwell wrote:
Hello,
I have recently been lucky enough to get the Cocoa portion of Mars working on Pharo 5.0. While there are some issues, it has a wonderful set of examples that allowed me create new Cocoa classes and delegate methods and see a straightforward path to learning how to use Coco widgets from Pharo.
I'd like to do that by creating appropriate Spec adapters, but unfortunately the new Spec booklet wasn't designed for that!
Can anyone give me any insight into creating (and using) a new Spec adapter? Maybe just some high level steps to help me orient my investigation into how Spec works?
Thank you,
Rob