Hi all,
I've just uploaded a package to the Inbox for review by the community:
http://source.squeak.org/inbox/Mirrors-cwp.2.mcz
It's a simple first step at creating a mirror API for Squeak. I've only implemented ObjectMirror and ObjectVmMirror, which provide high- and low-level reflection on an object. This implementation has a twist, however: it sends no messages to the object it's reflecting. That allows us to reflect on network proxies, ORM stubs, mock objects and the like without triggering any state changes.
As a proof of the concept, I've implemented a rudimentary non-invasive MirrorInspector. The main thing that's missing is non-invasive printing, which would take a bit of work to implement, but isn't necessary for a demo. To see it in action do try the following in a workspace.
WARNING: Read the comments carefully, and don't do this in an image you care about!
"This creates a very dangerous object" Object subclass: #Nuke instanceVariableNames: 'one two three' classVariableNames: '' poolDictionaries: '' category: 'Test'. class := Smalltalk at: #Nuke. class superclass: nil. inst := class basicNew.
"This is harmless" MirrorInspector inspect: inst.
"This will crash your image" inst yourself.
The implementation uses primitive 188 to directly execute CompiledMethods with the reflected object as the receiver, thus giving us access to the object's state without sending it a message.
So, what do you think?
Colin