problems with Rebindable

[chmike via Digitalmars-d-learn]

On Saturday, 21 May 2016 at 10:42:13 UTC, chmike wrote:
> source/app.d(23,27): Error: cannot implicitly convert 
> expression (one) of type immutable(Obj) to app.Info

Apparently Rebindable doesn't support polymorphism. This is 
hopefully fixable.

> source/app.d(43,5): Error: 'x1' must be of integral or string 
> type, it is a app.Info
> source/app.d(45,10): Error: cannot implicitly convert 
> expression (one) of type immutable(Obj) to app.Info

A Rebindable variable can't be used as a switch argument. This 
would require a change to the language rules. However, the static 
immutable object Infos.one can be used as a case argument.

The conclusion is that Rebindable doesn't cover the needs of a 
mutable object reference.


In the flyweight pattern we only need to compare object addresses 
and we also want to use the lazy pattern to instantiate the 
immutable instances.