[Grace-core] super in Grace

[James Noble]

> By gads, Batman!

sometimes I amaze even myself (as Han Solo would say)
I do like the idea of basing inheritance on a very simple "record  
algebra".

> I han't thought about allowing an object constructor with multiple  
> occurrences of the same method as legal /syntax/.  But: why not?

it would be a bit confusing, but not too bad, I think.

> What about multiple occurrences of the same field?  Not a problem,  
> because all fields have unique names, so it can't happen.

a field is just a getter and a setter method, so it can happen - but  
one of the fields would be redundant.

> If we allow that syntax, then there should be some way of getting to  
> the overridden method (i.e., the method in the (n-1)th  method  
> declaration)  What about
>
> 	self.1.myMessage
> 	self.2.myMessage
>
> to send to the (n-1)st and (n-2)nd method.  Ordinary message send is  
> self.0.message.  And no, you can't omit the self in these special  
> forms.

but how would you know?

This is why I prefer something along the lines of "call-next-method"  
or - "run-next-body" or something -
without being able to change the name - because it's clear what it  
does even in this kind of arrangement.
We don't have to keep track of which proto-object various fields or  
methods originally came from.

> I'm actually very tempted by this!  It will make delegation first- 
> class, something that I have long wanted.  If we don't' have  
> assignable parent slots (and I don't think that we should), an  
> object s can still explicitly delegate a message to an object other  
> by writing

> 	other.0.someMessage
>
> Here the .0 says: the final method for someMessage in the object  
> other, but self remains the receiver.
>
> Well, maybe it's not quite first class.   Messages sent to self from  
> other would go to s, but if s had no method, they would not be  
> delegated to other; they would just fail.

I'm mostly happy with first-class, or almost-first class delegation.
Self does it with "perform: m delegatingTo: x" which is really all you  
need.
If we can convince people, I'd prefer concatenation, perhaps with
delegation as an extra.

> Let me see if I can do that.

OK sure..

James