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Implement From<T> for Wrapping<T> and From<Wrapping<T>> for T #44937
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It doesn't explicitly list |
Can you point to an example of real code where these impls would be useful? |
Any real code that uses As a personal example, I dabbled with writing a Game Boy Advance emulator a while back; |
Sure, I agree that |
I am going to close this for now. I would be happy to consider an RFC if someone finds concrete use cases that would benefit from |
I guess for me this was more of an initial impression sort of thing. Using I think part of the problem was that when interacting with the standard library, syntax like |
Making porting any RNG not the worst experience ever, for starters. Or something like cyclic redundancy checks, which assumes twos-complement arithmetic and depends on a memoized array of coefficients. Basically any code where placing |
@myconix could you link to real code? |
https://github.com/libtom/libtomcrypt/blob/develop/src/hashes/md5.c for a less trivial example |
I am trying to see concretely what improvement there would be. |
Right now, Wrapping doesn't allow for operating with plain integers, even literals, That, combined with the fact that there's no succinct way to specify a Wrapping literal, means that EVERY integer literal in those code snippets would need a |
@myconix could you demonstrate a snippet of code ported from any one of those links into Rust,
|
I can't do that in a reasonable time frame. The quicker explanation is that they can all be reduced to:
Giving an error at compile time. To get this to work, you need to explicitly make the 4 wrapping as well:
This is a trivial example, but if I wanted to implement one of those examples in Rust, this problem gets worse proportional to the number of ops in the code. |
@myconix I am going to continue to insist on seeing:
because I really don't believe that adding these impls would improve the use cases you are writing about. I've locked the thread because I don't see the discussion here moving in a productive direction, but I would be willing to consider an RFC (however brief) that lays out concrete advantages of If anyone is interested in spearheading an RFC, make sure to include:
|
It would be nice if
std::num::Wrapping
supportedFrom<T>
andInto<T>
, at least whenT
is a numeric primitive. I assumed these impls would exist and was surprised to find that they do not.The text was updated successfully, but these errors were encountered: