On Wednesday, 25 November 2015 at 03:59:01 UTC, Steven
Schveighoffer wrote:
On 11/24/15 10:51 PM, tcak wrote:
I have seen a code a while ago, but even by looking at
documentation, I
couldn't have found anything about it.
Let's say I have defined an enum;
enum Status: ubyte{
Busy = 1,
Active = 2
}
and received a ubyte value from user.
ubyte userValue;
I want to switch over userValue, but that should depend on
Status.
switch( userValue ){
....
}
What I mean is that compiler should enforce values of enum
"Status" to
be declared in switch as it would be done with "final switch",
but as
you can guess, user might enter a value that is not defined by
Status.
Thus, I should be able to enter the case "default" as well.
All final switch does is ensure you are covering all possible
enums. It assumes that the value is already a valid enum value.
If you did final switch on userValue, it would require you
handle all 256 possible values for ubyte. So you would have to
cast first.
I remember it something like switch( userValue ) with( Status
){...},
but not sure about it. Maybe it was D1 code. Is there anything
like this
currently?
What this does (and yes, it should work) is make it so you
don't have to type "Status.Busy" within your case statements.
You can just type "Busy". That's all.
-Steve
As far as I see, "default" case is not allowed when final switch
is used. From compiler developer's perspective, it is meaningful
and I can understand, but thinking about use cases as I have
given an example, this limitation prevents writing "tight" code.
(That is the term I could have found to express I am trying to
say).
