[Reflectivity] simple #before and #after links working...

On 22 Mar 2015, at 11:41, Marcus Denker <[hidden email]> wrote:

On 22 Mar 2015, at 11:33, Ben Coman <[hidden email]> wrote:

That is very cool. But I need to ask the tough question - given that the feature freeze was three weeks ago, what do we gain by adding this in Pharo 4?  

* Is it needed for demonstrations that won't be based off latest features in Pharo 5 ?

* Are third party libraries expected to be based only off Pharo 4 MetaLink features, rather than additional MetaLink features it sounds like Pharo 5 will get ?

which means this slice should not impact anything

Because "should" being the operative word... is a slippery slope. If we have a philosophy of freezing features before a Release, then we should have the discipline to hold to that - at least in last 7 days before Release.

Yes, maybe we should postpone it… releasing is boring, I have to admit :-)

I will revert the change in the visitor… this way we are sure that we do not get any problems.

https://pharo.fogbugz.com/f/cases/15207/Undo-compiler-change-from-case-15196

I am really looking forward to that in Pharo5… it is (one of my) largest mistakes that after my PhD I did not focus on

getting Reflectivity into Pharo… it is still amazing, even 5 years later, I think. (but I am biased ;-)

Marcus

Simple after and before MetaLinks are taken into account, with just one check in #visitNode of the ASTTranslator that is

false when no links are there. (which means this slice should not impact anything)

For now this is for very simple MetaLinks: no parameters, no condition, no reification, no #instead/around, 

no meta-level modelling.

Here is a trivial example:

1) get a AST node from our example method:

sendNode := (ReflectivityExamples>>#exampleMethod) ast body statements first value.

2) then we define a link that is just #halt:

link := MetaLink new 

metaObject: Halt;

 selector: #now.

3) we set it:

sendNode link: link.

4) when we now execute the method, we get a halt:

ReflectivityExamples new exampleMethod

5) to get rid of it, uninstall the link:

link uninstall.

If you look at the byte code, you see that it compiles the link to the code:

25 <20> pushConstant: Halt

26 <D1> send: now

Marcus