On 18 May 2014, at 21:42, Johan Fabry <jfa...@dcc.uchile.cl> wrote:
>
> I understand, thanks for the info.
>
> Let me simplify my question: Using slots is there a reasonably
> straightforward way for me to intercept variable accesses in all methods
> within a class?
Yes, you can make a special slot subclass and this defines than the semantics
of the slot. You have full control of what code to emit.
> This so that I can transparently redirect them to a dictionary lookup.
there will be Dictionay based slots coming with Pharo4, no need to roll your
own for that.
In addition, I want to add support for Reflectivity meta links on slots. This
means that instead of changing the class definition,
you will be able to put a MetaLink on the slot definition (before, after,
around/instead). This is for the more “reflective” use cases.
Now this is all in an early state.. the idea is to finish all this over the
summer :-)
With Camille we did a quick 20 minute prototype of the whole thing: Subclass of
Slot. Opal calles #emitStore: and #emitRead:
on slots. the abstract slot has a fall-back that just uses reflection:
emitValue: aMethodBuilder
aMethodBuilder
pushLiteral: self;
pushReceiver;
send: #read:
while you can implement it yourself and emit the bytecode that
you need. e.g. for the ivarSlot subclass it is
emitValue: methodBuilder
methodBuilder pushInstVar: index.
making Ivar Slots be as efficient as instance variables now.
Marcus
