On Friday, 27 July 2018 at 14:38:27 UTC, Steven Schveighoffer
wrote:
On 7/27/18 9:29 AM, aliak wrote:
Ok, thanks to Simen from another post [0], I just figured out
what the correct constructor and factory method for a template
wrapper should be:
https://run.dlang.io/is/S4vHzL
struct W(T) {
T val;
this(U : T, this This)(auto ref U val) {
this.val = val;
}
}
auto wrap(T)(auto ref T t) {
return W!T(t);
}
Seems to catch all cases!
And instantiate a new template for all mutabilities. Whereas
inout would only instantiate one (and disallows modification of
val if not const or immutable).
-Steve
If you change the ctor to be inout then you get (from the link
above):
onlineapp.d(4): Error: cannot implicitly convert expression val
of type onlineapp.C to inout(C)
onlineapp.d(28): Error: template instance
`onlineapp.W!(C).W.__ctor!(C)` error instantiating
onlineapp.d(4): Error: cannot implicitly convert expression val
of type S1 to inout(S1)
onlineapp.d(44): Error: template instance
`onlineapp.W!(S1).W.__ctor!(S1)` error instantiating
onlineapp.d(4): Error: cannot implicitly convert expression val
of type onlineapp.C to inout(C)
onlineapp.d(9): Error: template instance
`onlineapp.W!(C).W.__ctor!(C)` error instantiating
onlineapp.d(52): instantiated from here: wrap!(C)
onlineapp.d(4): Error: cannot implicitly convert expression val
of type const(C) to inout(const(C))
onlineapp.d(9): Error: template instance
`onlineapp.W!(const(C)).W.__ctor!(const(C))` error instantiating
onlineapp.d(53): instantiated from here: wrap!(const(C))
Am I applying inout incorrectly?
