• Freddy (5/5) Jul 08 2015 std.variant's Algebraic
• Andrei Alexandrescu (4/11) Jul 08 2015 No. The code is incorrect in several places.
• Freddy (12/13) Jul 08 2015 peek returns a pointer to a stack variable
• Freddy (2/5) Jul 08 2015 + I meant that it can't be used in @safe code
• Andrei Alexandrescu (3/7) Jul 08 2015 I see. Indeed that method can't be used in safe code - the others

"Freddy" <Hexagonalstar64 gmail.com> writes:

std.variant's Algebraic 
(https://github.com/D-Programming-Language/phobos/blob/master/std/variant.d)
seems very complex for what it's trying to do and is also unsafe.

Is it worth writing a simpler replacement?

Something like this 
https://github.com/Superstar64/tagged_union/blob/master/source/tagged_union.d ?

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

On 7/8/15 4:31 PM, Freddy wrote:
 std.variant's Algebraic
 (https://github.com/D-Programming-Language/phobos/blob/master/std/variant.d)
 seems very complex for what it's trying to do and is also unsafe.

What's unsafe about it?

 Is it worth writing a simpler replacement?

 Something like this
 https://github.com/Superstar64/tagged_union/blob/master/source/tagged_union.d
 ?

No. The code is incorrect in several places.


Andrei

"Freddy" <Hexagonalstar64 gmail.com> writes:

On Wednesday, 8 July 2015 at 21:34:01 UTC, Andrei Alexandrescu 
wrote:
 What's unsafe about it?

peek returns a pointer to a stack variable

import std.variant;
import std.stdio;

void main()
{
     Algebraic!(int,string) a = "a";
     string* b = a.peek!string;
     a = 0;
     writeln(b.length);
}

"Freddy" <Hexagonalstar64 gmail.com> writes:

On Wednesday, 8 July 2015 at 22:19:52 UTC, Freddy wrote:
 On Wednesday, 8 July 2015 at 21:34:01 UTC, Andrei Alexandrescu 
 wrote:
 What's unsafe about it?


+ I meant that it can't be used in  safe code

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

On 7/8/15 6:27 PM, Freddy wrote:
 On Wednesday, 8 July 2015 at 22:19:52 UTC, Freddy wrote:
 On Wednesday, 8 July 2015 at 21:34:01 UTC, Andrei Alexandrescu wrote:
 What's unsafe about it?


 + I meant that it can't be used in  safe code

I see. Indeed that method can't be used in safe code - the others 
should. -- Andrei