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digitalmars.D.learn - Safer enum casts

reply bearophile <bearophileHUGS lycos.com> writes:
If I have an enum of chars, and I have a variable that contains a generic char,
I may want to convert the second to an instance of the first one, safely (a
normal cast is enough to do it unsafely). Is it a good idea to give this
purpose to to!() (this idea is currently not implemented)?


import std.conv: to;
enum Foo : char { a = 'A', b = 'B' }
void main() {
    Foo r1 = cast(Foo)'A'; // OK
    Foo r2 = cast(Foo)'X'; // error undetected
    Foo r3 = to!Foo('A');  // OK
    Foo r4 = to!Foo('X');  // error detected
}

Bye,
bearophile
Feb 01 2011
parent reply Jesse Phillips <jessekphillips+D gmail.com> writes:
bearophile Wrote:

 If I have an enum of chars, and I have a variable that contains a generic
char, I may want to convert the second to an instance of the first one, safely
(a normal cast is enough to do it unsafely). Is it a good idea to give this
purpose to to!() (this idea is currently not implemented)?

I believe this is exactly what std.conv.to should do. It should be the safest and recommended way to do conversions. I have a request in for preventing removal of qualifiers: http://d.puremagic.com/issues/show_bug.cgi?id=5307
Feb 01 2011
parent bearophile <bearophileHUGS lycos.com> writes:
Jesse Phillips:

 I believe this is exactly what std.conv.to should do. It should be the safest
and recommended way to do conversions.

http://d.puremagic.com/issues/show_bug.cgi?id=5515 Bye, bearophile
Feb 01 2011