NO_STD

[zendurix]

I have succesfully implemented no_std with hasbrown crate (to enable no_std use with default-features = false
It passed no_std check (https://github.com/mystor/cargo-no-std-check)

[XVilka]

I am not sure use crate::lib::*; is a good practice. The idea to wrap everything is good, but probably better to import only used modules. Please also add the corresponding CI job from #238

[XVilka]

Also CI is failing:

error[E0432]: unresolved imports `rand::thread_rng`, `rand::ChaChaRng`
 --> tests/unionfind.rs:5:12
  |
5 | use rand::{thread_rng, ChaChaRng, Rng, SeedableRng};
  |            ^^^^^^^^^^  ^^^^^^^^^ no `ChaChaRng` in the root
  |            |
  |            no `thread_rng` in the root
warning: unused import: `SeedableRng`
 --> tests/unionfind.rs:5:40
  |
5 | use rand::{thread_rng, ChaChaRng, Rng, SeedableRng};
  |                                        ^^^^^^^^^^^
  |
  = note: #[warn(unused_imports)] on by default
warning: unused import: `Rng`
 --> tests/unionfind.rs:5:35
  |
5 | use rand::{thread_rng, ChaChaRng, Rng, SeedableRng};
  |                                   ^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0432`.
error: Could not compile `petgraph`.

[zendurix]

Should all test be included in no_std? this will require some additional work

[XVilka]

Yes.

[zendurix]

Maybe leave thoose tests that uses RNG outside of no_std?

[XVilka]

Yes, that makes sense.

[zendurix]

I have implemented requested changes, all tests are passing in both std and no_std

[XVilka]

Looks better, thanks!
Could you please also add a no_std CI job?

[zendurix]

@XVilka
I am not sure how to do that, should I just add this line at the end of travis.yml ?
&& cargo test --all --no-default-features --features="graphmap","stable_graph","matrix_graph"

[XVilka]

@zendurix you can just take .travis.yml from the old PR: https://github.com/petgraph/petgraph/pull/238/files#diff-354f30a63fb0907d4ad57269548329e3

[XVilka]

Also I am not sure, instead of adding #[cfg(feature="std")] before every println! maybe it's better to define own macro or function and do the switch once?

By the way, you can also use https://github.com/hobofan/cargo-nono for checks.

[zendurix]

Also I am not sure, instead of adding #[cfg(feature="std")] before every println! maybe it's better to define own macro or function and do the switch once?

By the way, you can also use https://github.com/hobofan/cargo-nono for checks.

I can think of smth like

pub fn print(args) {
   #[cfg(feature = "std)]
   println!(args)
}

But I am not very good with macros, and I am not sure how to do this

[XVilka]

Maybe something like

macro_rules! no_std_println {
  ($(t:tt)*) => {
    #[cfg(feature = "std")]
    {
      println!($($t)*);
    }
  };
}

[zendurix]

I see problems with CI (cause old PR have feature no_std) I will impl this macro and fix CI later today

[XVilka]

@zendurix have you had any luck with this update? Could you please rebase because we migrated from Travis CI to GitHub Actions?

[XVilka]

@zendurix could you please rebase your PR?

[bluss]

HashMap is used in the public API - this PR would mean that public API changes breakingly based on a cargo feature, and that's not an allowed usage of cargo features in general. This can't be integrated with this design, unfortunately.

The whole approach to HashMap needs to change somehow. I don't know if using hashbrown is necessary. Keep it simple and incremental, is it possible to support compiling without HashMap?

[chaosprint]

Hi, this is such a wonderful job. Is there any plan that the rebase can be done in the near future?

[indietyp]

0.7.0 will have no-std support, until this version has landed I will keep this PR open.