I imagine the repository link (https://github.com/parallel-systems/bit-struct) is not supposed to have that one hyphen in the user name.

• need to run several tests in macros to cover all signed/unsiged variants

• u{x}! macros
• overly sized struct
• incorrect field types
• overly sized enums

technically according to docs what we are doing is UB, but given our invariants perhaps it actually isn't (all tests pass at least on MacOS)... and it seems to work on cortex processors.
This should be pretty easy to fix by using core::ptr instead.

The readme contains a full example of use case, it's would be nice to have an compiled example of what item are generated in the doc, like https://docs.rs/snafu/0.6.10/snafu/guide/examples/basic/index.html for example.

This is more easy to understand what macro do for the user.

Every invocation of bit_struct! and enums! fails because of this:

error[E0463]: can't find crate for `serde`
  --> src/leaf6.rs:6:1
   |
6  | / bit_struct! {
7  | |
8  | |     pub struct ThermalFeatures(u32) {
9  | |         DTS: bool,
...  |
27 | |     }
28 | | }
   | |_^ can't find crate
   |
   = note: this error originates in the derive macro `$crate::serde::Deserialize` which comes from the expansion of the macro `bit_struct` (in Nightly builds, run with -Z macro-backtrace for more info)

Good afternoon! I've been writing something heavily using this library but I came across a roadblock.

Problem

The way GetSet are created means that I need mutability of a bit struct to be able to read from it, which is not necessary nor possible in some cases.

Example

use bit_struct::*;

bit_struct! {
	// Useless struct for demonstration purposes
	pub struct Halfling(u8) {
		first_half: u4,
		second_half: u4
	}
}

impl Display for Halfling {
	// note immutability of self
	fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
		writeln!(f, "The halves together make {}", self.first_half.get().value() + self.second_half.get().value())
	}
}

This will not compile because .first_half() and .second_half() take &mut self to make their GetSets, which the signature of Display::fmt doesn't permit. In this use case I don't need to modify the Halfling at all and can't, but it insists it must be mutable.

Solution?

I understand why GetSet needs to be constructed with a mutable reference, so I propose a Get or similarly named struct with read-only privileges that will work in this context. How that would work, I'm not sure.

By convention it would make sense to change all generated field GetSet functions to mut_[field name] and make the existing ones return Get structs instead, but this would break everything wholesale. How would you prefer to implement this? I would be willing to do the legwork in a PR.

Both lead me to https://github.com/parallel-systems/bit-struct but the correct url is https://github.com/parallelsystems/bit-struct/

• for example, support N-long bytes as storage.