std.digest toHexString

Carl Sturtivant via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Thu Mar 16 09:47:14 PDT 2017


On Thursday, 16 March 2017 at 16:21:08 UTC, Adam D. Ruppe wrote:
> On Thursday, 16 March 2017 at 16:13:33 UTC, Carl Sturtivant 
> wrote:
>>     string ans = md5Of(arg).toHexString();
>
> That is a major D design flaw biting you the same way it has 
> bitten so many others.
>
> See the red box in my documentation fork:
>
> http://dpldocs.info/experimental-docs/std.digest.digest.toHexString.2.html
>
> toHexString returns a static array... on the stack. Then the 
> stupid language not only implicitly casts it to immutable, it 
> also implicitly slices it, giving you a reference to mutable, 
> temporary data pretending to be permanent, immutable data.

Silently <expletive-deleted> cast to immutable without 
copying!??!! This is so wrong.

Yet the documentation says there's a toHexString that returns a 
string.
http://dlang.org/phobos/std_digest_digest.html#.toHexString
I don't understand the overload resolution implied at this link. 
How is a toHexString selected in
         string ans = md5Of(arg).toHexString();
?




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