[Grace-core] [A Graceful Blog] Comment: "From Lancaster to Portland"

[James Noble]

> I would include "brand someName" in the type signature (along with method add()and(), etc.)   For the purpose of type checking , an brand operates just like a parameterless method.    The only difference is that the method's name is really #someName#, and you can't request a method with a name like that, because the corresponding message request is a syntax error.

OK - yes that makes sense. You could have multiple brands per object etc.

If you wanted to typecase on this, you'd need to look at the brand *and* require particular methods
to fix the resulting structural type --- this is why e.g. Donna M's Unity has each (user visible) brand
packaged together with a structural type - you only match if you have both the brand and the methods
you think belong with that brand.

For consistency / understandability, if we go this way, we'd probably want to make brands actually different from methods;
so they'd display as "brands" in a debugger, and actually couldn't be called etc.

Or we could just go with a simple language and do things by convention - perhaps with defs or vars.

But there is also the issue - although we can get this to work - as Andrew puts it on another topic:

> Remember, we have to be able to explain this stuff to students.  If I were  novice student, I would be very confused ...

the issue here is: examples in almost any other language will look simpler because of their "implicit branding"
(even in things like O'CAML) 

James