no-std support

[henrikssn]

I need precisely the GenericDecimal type in my (embedded) project but unfortunately I don't have a heap available and fraction links towards std.

Are there any plans to support (a limited set) of this crate for no-std environments?

[dnsl48]

Hi @henrikssn, thanks for bringing this up! Definitely a want-to-have feature for us. However, at this point, it's still in the very early stage and most likely not gonna be released for a while yet.
Currently, we're gathering user stories (and requirements) for the no-std use cases. If you could share yours, that would be very helpful!

Thanks!

[onkoe]

Having difficulties with this, too. Hope to see some progress soon! :)

[onkoe]

The num-rational crate has very similar functionality and works great #[no_std]! At least for my usage, it was nearly a drop-in replacement.

Nonetheless, I'd still enjoy support in this crate too! ✨

[dnsl48]

Hi @onkoe, thank you for the feedback!
I am wondering about your use case. Do you use BigInt or do you have predetermined range of acceptable numbers and can pre-validate the stack overflow bounds?

[onkoe]

My use of this crate was pretty limited: I only had GenericFraction<u16> and Decimal in use, as I'm making a parser for structures that are way less than a KiB! So, at least for me, BigInt isn't required.

For all the given structures in my parser, the standard gives me the range of any potential values, so it's not much of a worry on my end. In fact, each fraction/decimal in the standard is represented by a maximum of two bytes, so my usage is about as friendly as possible! :D

If you have any additional questions, please let me know! You can see the specifics of my usage in this commit: onkoe/liboptic@3cb68f9

[onkoe]

Also, please note that my usage might be different from most other folks using fraction. I plan to make my crate "no_alloc", so I'm not using the dynamic types.

I think those are more difficult - my apologies for not being able to assist with developing their expectations on no_std.

[Chris--B]

Also here to +1 no_std support. I'm working on a project targeting a Pi Pico Thumb-based M0+ processor. We do have a heap, but we do not have std nor an OS, so this crate doesn't compile when we try it.

num-rational looks like it solves our immediate use - doing float-ish math on a system with no FPU, so we'll give it a try. 🙏

[dnsl48]

Thank you for the feedback, that's really helpful!
@Chris--B I'd like to ask about your use-case for decimals/fractions. Are you working on parsing & interpreting data, or are you looking for lossless math?