Unfortunately it is not possible to write this
import std.typecons;
class Info{...}
rebindable!Info x;
I get the following error message
source/app.d(11,3): Error: template std.typecons.rebindable
matches more than one template declaration:
/usr/include/dmd/phobos/std/typecons.d(1675,14):
rebindable(T)(T obj) if (is(T == class) || is(T == interface) ||
isDynamicArray!T || isAssociativeArray!T)
and
/usr/include/dmd/phobos/std/typecons.d(1694,14):
rebindable(T)(Rebindable!T obj)
This would have been equivalent to define a mutable reference to
an object of type Info and allow me to write this
alias rebindable!Info InfoR;
InfoR x;
Unfortunately I didn't manage to get something compiling with
rebindable. I don't understand how I'm supposed to use it.
Note that I'm designing a library that I would like intuitive to
use. Hacking around the problem won't cut it.
I need a type defining a mutable reference to an immutable
object. Rebindable doesn't give me that apparently.
I need something allowing me to write this
interface Info {...}
class MyInfos {
static class Obj : Info {...}
static immutable Obj one = new immutable Obj(...);
}
mutableObjectRef!Info x1, x2;
assert(x1 is null);
assert(x1 == null);
x1 = MyInfos.one;
assert(x1 is MyInfos.one);
assert(x1 == MyInfos.one);
x2 = x1;
switch(x1){
case MyInfos.one: ... ;
default:...;
}
x1 must have the semantic of an object reference, support
polymorphism, allowing to down or up cast and of course access
immutable members and methods.
MyInfos.one is an object reference that I shouldn't be allowed to
modify. I can't use a function because it needs the value
semantic so I can use it as a case argument in a switch.
It doesn't seam that this is what rebind provides. It looks like
mutableObjectRef should be a templated struct. But I'm not
experienced enough in D to implement it. I don't know if its only
possible.
