Re: [Help-smalltalk] [ANN] Mirrors for GST

[Gwenaël Casaccio]

On 28/02/2012 15:22, Paolo Bonzini wrote:
> Il 28/02/2012 15:00, Gwenaël Casaccio ha scritto:
> > I've made a MirrorPrimitive and two pragmas; the first pragma calls the
> > primitive
> > but the second has an extra argument an error block (i.e. vmPrimitive
> > for: ... at: ifFailed: [])
> > Thus no exceptions are raised (and thus no possible leaked vmPrimitves
> > objects).
> > The primitive number is added at the end by the pragma. I've added the
> > compiled
> > method as an extra parameter to the execute_primitive function.
> >
> > classFor: anObject [
> > <mirrorPrimtive: VMpr_Object_Class>
> > ]
> >
> > for: anObject at: anIndex ifFailed: aBlock [
> > <mirrorPrimtiveWithBlock: VMpr_Object_basicAt>
> >      ^aBlock value
> > ]
> Do you need the second?  Perhaps you can just call ^self
> primitiveFailed, and catch the exception in the caller.  Mirror
> primitives that can fail shouldn't be on a fast path, should they?
> Otherwise looks good.
>
> Paolo

Hello,
about the exceptions. frankly I'm not sure about mirrors errors 
handling: I like to force the user to handle errors (for Mirrors) but 
there is one exception #dnu: errors (returning ^ self is too "dangerous" 
it will be a pain to debug the application). Thus if I raise an 
exception specially with a mirror an object could capture exception and 
the mirror and you know the next. In fact I would like to understand a 
bit more what is the best approach maybe "safer" exceptions are better, 
an object could capture them but cannot break the encapsulation of the 
exception.

And since I'm talking about exceptions what about a process that handle 
exceptions like Erlang : It will capture all the exception of the 
running image could handle some cases, and in the worst case could 
restart the service (the image with a kind of OSProcess) - just a vague idea

Cheers,
Gwen