Unfortunately you cannot escape from asInstanceOf . Forcing
self:MapperType the type of "this" will be TimeStamp with MapperType
violating the constraint for the type of the first parameter of
MappedDateTime :T <: Mapper[T].
Regards
Giuseppe
On 3 Set, 07:08, Naftoli Gugenheim <naftoli...@gmail.com> wrote:
> So I guess you can't escape the asInstanceOf. Can you successfully give the
> trait a self-type of this: MapperType =>, or declare it to extend
> Mapper[MapperType], without running into problems elsewhere?
>
> -------------------------------------
>
> harryh<har...@gmail.com> wrote:
>
> I've been handling this with traits, for example I have something like
> so:
>
> trait Timestamp[MapperType <: Mapper[MapperType]] {
> object xdatetime extends MappedDateTime[MapperType](this.asInstanceOf
> [MapperType])
>
> // all sorts of utility functions for dealing with timestamps
>
> }
>
> Then I can do
>
> class Foo extends LongKeyedMapper[Foo] with IdPK with Timestamp[Foo] {
> // additional fields that are Foo specific
>
> }
>
> I have quite a few traits similar to Timestamp at this point
> corresponding to various fields that appear in lots of different
> tables in my application.
>
> -harryh
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