> On 29 Apr 2015, at 22:59, Glenn Cavarlé <gl...@cavarle.fr> wrote:
>
> Hi,
>
> I'm playing with Slots and MethodWrappers to customize instVar
> reading/writing and method calls.
> In my experiments, Slots and MethodWrappers hold meta-description objects
> used at runtime to apply some filters, validations and to compose or
> delegate methods behavior.
>
Interesting!
> I'm really interested in the progress of MetaLink, I saw that it will be
> possible to use hooks like #instead or #arround.
> Are these hooks can replace the use of MethodWappers ?
Yes!
> Will it be possible to call a MetaObject's method instead of a method's body
> and with the passed arguments ?
>
Yes, this will work very soon… in a simple version (only one replace link
allowed).
(Later this will be generalized AOP style as an #around with the possibility to
“proceed”
to the replaced node).
What I am porting now from the prototypes is the functionality to hand arguments
over to meta objects.
before links on methods are already working:
link := MetaLink new
metaObject: [ self halt ].
(ReflectivityExamples>>#exampleMethod) ast link: link.
execute it:
ReflectivityExamples new exampleMethod.
(ReflectivityExamples>>#exampleMethod) symbolic
"'21 <20> pushConstant: [ self halt ]
22 <C9> send: value
23 <77> pushConstant: 2
24 <21> pushConstant: 3
25 <B0> send: +
26 <7C> returnTop’"
(This example, too, shows that a block can be a meta object, this means that
this
can be used as a very easy to use instrumentation framework, too, without the
need
to create explicit classes and methods for meta objects).
> The announcement of meta-levels gives me ideas, would not it be interesting
> to have something like meta-layers?
Yes!
> For instance, in order to address a layer with no MetaObjects execution, a
> layer with MetaObjects for logging or breakpoints, an other layer with
> custom MetaObjects, etc.
> I don't see how it would be possible to limit the scope of the active layers
> configuration, just for a block evaluation for exemple... From RFMetaContext
> maybe, but how ?…
One thing I want to add is to make the condition (optionally) into an object
and then allow reflectivitly to turn on/of links without having to actually
change
the #condition: itself.
Then links themselves could target these control meta objects…
It is definitly interesting. E.g. one might want to have break points active,
yet run the tests with them disabled.
Marcus
