Casting to anonymous class with a given method

Dear all,I have read somewhere on some scala book that it is possible to define generics in an anonymous way.
1) I can't find it .. it looked to me that you can do a generic for example [AnyRef with stop()] , the syntax is wrong, but the idea is that a function receiving this kind of object can call the stop() method on it.
2) Can this be used also to cast objects?
Best Regards
Edmondo

Dear all,I have read somewhere on some scala book that it is possible to define generics in an anonymous way.
1) I can't find it .. it looked to me that you can do a generic for example [AnyRef with stop()] , the syntax is wrong, but the idea is that a function receiving this kind of object can call the stop() method on it.
2) Can this be used also to cast objects?
Best Regards
Edmondo

Dear all,I have read somewhere on some scala book that it is possible to define generics in an anonymous way.
1) I can't find it .. it looked to me that you can do a generic for example [AnyRef with stop()] , the syntax is wrong, but the idea is that a function receiving this kind of object can call the stop() method on it.
2) Can this be used also to cast objects?

Best Regards
Edmondo

The magic phrase you're after is "structural typing", Google should give you plenty of useful hits.


On 21 December 2011 13:38, Edmondo Porcu <edmondo.porcu@gmail.com> wrote:

Dear all,I have read somewhere on some scala book that it is possible to define generics in an anonymous way.
1) I can't find it .. it looked to me that you can do a generic for example [AnyRef with stop()] , the syntax is wrong, but the idea is that a function receiving this kind of object can call the stop() method on it.
2) Can this be used also to cast objects?
Best Regards
Edmondo

Can one use structural typing with generics?
def method[T<:{def greet():Unit}]: List[T] ?

Best Regards

2011/12/21 Kevin Wright <kev.lee.wright@gmail.com>

The magic phrase you're after is "structural typing", Google should give you plenty of useful hits.


On 21 December 2011 13:38, Edmondo Porcu <edmondo.porcu@gmail.com> wrote:

Dear all,I have read somewhere on some scala book that it is possible to define generics in an anonymous way.
1) I can't find it .. it looked to me that you can do a generic for example [AnyRef with stop()] , the syntax is wrong, but the idea is that a function receiving this kind of object can call the stop() method on it.
2) Can this be used also to cast objects?
Best Regards
Edmondo

short answer: yes.

but your example method doesn't really make sense. what you have written there means:
T must be something that has a greet-method.
now let's say you have some classes, some traits and some types which match here. you pass in one of them as a type parameter. how are you going to figure out which one was passed in? you need to know, because you have to return List[T]

def method:List[{def greet():Unit}] makes more sense

-------- Original-Nachricht --------
> Datum: Tue, 27 Dec 2011 11:22:08 +0100
> Von: Edmondo Porcu
> An: Kevin Wright
> CC: scala-user
> Betreff: Re: [scala-user] Casting to anonymous class with a given method

> Can one use structural typing with generics?
>
> def method[T<:{def greet():Unit}]: List[T] ?
>
> Best Regards
>
> 2011/12/21 Kevin Wright
>
> > The magic phrase you're after is "structural typing", Google should give
> > you plenty of useful hits.
> >
> >
> >
> > On 21 December 2011 13:38, Edmondo Porcu
> wrote:
> >
> >> Dear all,
> >> I have read somewhere on some scala book that it is possible to define
> >> generics in an anonymous way.
> >>
> >> 1) I can't find it .. it looked to me that you can do a generic for
> >> example [AnyRef with stop()] , the syntax is wrong, but the idea is
> that a
> >> function receiving this kind of object can call the stop() method on
> it.
> >>
> >> 2) Can this be used also to cast objects?
> >>
> >> Best Regards
> >>
> >> Edmondo
> >>
> >
> >
> >
> >