Enum conversion

[Russel Winder]

On Tue, 2020-04-21 at 15:48 -0400, Steven Schveighoffer via
Digitalmars-d-learn wrote:
[…]
> 
> 1. it's shorter and prettier.
> 2. No cast (I avoid using cast whenever I can).
> 3. No gotcha type conversions.

Works for me, you have me convinced. :-)

> e.g. for point 3:
> 
> enum ZoneMember { // : int
>    One = 1,
>    Two = 2,
>    ReallyBig = 4567,
> }
> 
> auto b1 = ubyte(ZoneNumber.One); // 1 (compiler uses VRP to make this
> work)
> auto b2 = ubyte(ZoneNumber.ReallyBig); // Compiler error
> 
> vs.
> 
> auto b1 = cast(ubyte)ZoneNumber.One; // 1
> auto b2 = cast(ubyte)ZoneNumber.ReallyBig; // b2 == 215 (truncated)
> 
> vs.
> 
> auto b1 = to!ubyte(ZoneNumber.One); // 1
> auto b2 = to!ubyte(ZoneNumber.ReallyBig); // runtime error

QED.

Though for converting a ulong to a ubyte, I am assuming to!ubyte(x) is
the right tool for the job.

[…]
> pragma(msg, typeof(ZoneNumber.One).stringof); // ZoneNumber

Which is as it should be really. I was clearly having a mental
aberration. Anyway, the probem is now solved! :-) Thanks for your
input, much appreciated.
 
-- 
Russel.
===========================================
Dr Russel Winder      t: +44 20 7585 2200
41 Buckmaster Road    m: +44 7770 465 077
London SW11 1EN, UK   w: www.russel.org.uk

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