Re: ignorance: customizable immutables?

See my ideas in the thread, "The cake’s problem, dotty design and the 
approach to modularity. 
<https://groups.google.com/forum/#!topic/scala-language/WcnHXjAJaKg>"

Throw away virtual inheritance and so you can have multiple orthogonal 
interfaces implemented on the same data. Thus, the type of your List would 
be List[A or ADifferent]. In my idea, the compiler would insure your 
asCapitalA would automatically be invoked with the necessary boiler-plate 
so that it calls the correct interface. The result type of your map would 
be the intersection of types `A or ADifferent`.

Afaics, the point is we stop subsuming to Any and retain the composition in 
the types in the new DOT (Dotty) calculus. This can eliminate the need to 
use virtual inheritance, especially if the compiler can be made smart 
enough to automatically handle all the boiler-plate for manual injection.

Btw, I was advocating for an intersection type for Scala since (circa 2011 
afair) before I became aware of the DOT calculus. I filled up the Github 
gist questionaire on what the semantics of the intersection type should be:

https://issues.scala-lang.org/browse/SUGGEST-22

Whoops,  I realized I juxtaposed intersection and disjunction in my 
messages.


On Wednesday, June 17, 2015 at 1:44:58 AM UTC+8, raould wrote:
>
> >   List(new A, new A{ override def foo = "different" }).map(x.asCapitalA) 
> > If `asCapitalA` has mutating side-effects, you retain the distinct `foo` 
> > behavior.  If, in contrast, it creates a new immutable A, your unique 
> `foo` 
> > behavior is lost. 
>
> Are there any approaches people like to use to get immutables that 
> respect whatever customization has been done -- some way to assemble 
> components and then still be able to frob() them and get a new 
> immutable copy that retains the customizations? Concisely, robustly? I 
> mean in any programming language. 
>

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