Feat: support format!("{:x}") notation for hexadecimal formatting

[remybar]

Proposal for issue #6261.

This PR adds a LowerHex trait as existing in Rust, to be able to format integer values to hexadecimal using the {:x} notation. Rust also provides a UpperHex trait to format the string in upper case but I don't know if it's really useful.

This PR also implements this trait for:

• unsigned integers (from u8 to u256),
• felt252
• NonZero
• common Starknet types such as ContractAddress and ClassHash using the existing into_felt252_based module.

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This change is 

[orizi]

Reviewed 3 of 8 files at r1.
Reviewable status: 3 of 8 files reviewed, 4 unresolved discussions (waiting on @remybar)

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Cargo.lock line 241 at r1 (raw file):

]

[[package]]

revert file.

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corelib/src/fmt.cairo line 320 at r1 (raw file):

> of LowerHex<T> {
    fn fmt(self: @T, ref f: Formatter) -> Result<(), Error> {
        f.buffer.append(@"0x");

shouldn't be part of it. same as rust.

Code quote:

        f.buffer.append(@"0x");

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crates/cairo-lang-semantic/src/inline_macros/write.rs line 142 at r1 (raw file):

        WriteMacro::NAME
    }
}

run the same rust fmt as the CI.
(./script/rust_fmt.sh)

Code quote:

fn get_macro_name(with_newline: bool) -> &'static str {
    if with_newline {
        WritelnMacro::NAME
    } else {
        WriteMacro::NAME
    }
}

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crates/cairo-lang-semantic/src/inline_macros/write.rs line 527 at r1 (raw file):

    } else {
        return Err("Unsupported formatting trait: only `Display` and `Debug` are supported");
    };

Suggestion:

    let fmt_type = match formatting_spec.as_str() {
        "" => FormattingTrait::Display,
        "?" => FormattingTrait::Debug,
        "x" => FormattingTrait::LowerHex,
        _ => return Err("Unsupported formatting trait: only `Display`, `Debug` and `LowerHex` are supported"),
    };

[remybar]

Hi @orizi !

Thanks for the review. I did the required changes.

[orizi]

Reviewed 1 of 4 files at r2.
Reviewable status: 4 of 8 files reviewed, 1 unresolved discussion (waiting on @remybar)

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crates/cairo-lang-semantic/src/inline_macros/write.rs line 527 at r1 (raw file):

    } else {
        return Err("Unsupported formatting trait: only `Display` and `Debug` are supported");
    };

why not match?

[orizi]

please view at reviewable: https://reviewable.io/reviews/starkware-libs/cairo/6297#-

Reviewable status: 4 of 8 files reviewed, 1 unresolved discussion (waiting on @remybar)

[orizi]

Reviewable status: 4 of 8 files reviewed, 1 unresolved discussion (waiting on @remybar)

a discussion (no related file):
@gilbens-starkware for 2nd eye.

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[remybar]

why not match?

Because I didn't noticed the match but just the change related to the error message... 🫣
Sorry, I also replaced the if/else by a match as suggested ;-)

[gilbens-starkware]

Reviewable status: 4 of 8 files reviewed, 1 unresolved discussion (waiting on @orizi and @remybar)

[orizi]

Reviewed 1 of 8 files at r1, 1 of 4 files at r2, 2 of 2 files at r3, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @remybar)

[orizi]

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @remybar)

[orizi]

Reviewed 6 of 6 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @remybar)

[mkaput]

Reviewed 1 of 1 files at r5.
Reviewable status: all files reviewed (commit messages unreviewed), all discussions resolved (waiting on @Arcticae, @Draggu, and @piotmag769)

[orizi]

Reviewed 1 of 1 files at r5, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @remybar)