[Vm-dev] Re: [Pharo-dev] Proxy DNU vs CannotInterpret. (Ghost
related)
Andres Valloud
avalloud at smalltalk.comcastbiz.net
Sat Mar 26 04:06:15 UTC 2016
On 3/25/16 18:53 , Eliot Miranda wrote:
> Hi Andres,
>
> On Thu, Mar 24, 2016 at 11:20 PM, Andres Valloud
> <avalloud at smalltalk.comcastbiz.net
> <mailto:avalloud at smalltalk.comcastbiz.net>> wrote:
>
>
> It's there to avoid crashes when people implement proxy classes and
> Instantiate before remembering to implement doesNotUnderstand: (a
> recursive doesNotUnderstand: causes the VM to exit).
>
>
> Strange. The VM knows plenty of objects that could arguably
> understand a message such as
>
> object: anObject doesNotUnderstand: aMessage
>
>
> What's to stop someone deleting, say, Context>>object:doesNotUnderstand:
> ? At some point there has to be a message handler. Why bother
> complicating things by allowing there to be no doesNotUnderstand: ?
To me, the case of omitting a method in a new subclass of nil seems
different enough from the case of deleting a method from Context to
warrant a different outcome. We can already see that omission of
doesNotUnderstand: has already led to the creation of classes such as
ProtoObject, i.e. extra complexity.
Andres.
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