#fluent #debug #display #format #no-std

no-std fn-formats

Format trait wrappers for Fn(&mut Formatter) -> fmt::Result

5 releases

0.0.5 Sep 5, 2020
0.0.4 Sep 2, 2020
0.0.3 Sep 1, 2020
0.0.2 Aug 30, 2020
0.0.1 Aug 30, 2020

#260 in Debugging


501 lines


Lib.rs Crates.io Docs.rs

Rust 1.40.0 Build Status Crates.io - License

GitHub open issues open pull requests crev reviews

This is a small shim library for passing closures where you need one of the format traits (including Binary etc.).


Please use cargo-edit to always add the latest version of this library:

cargo add fn-formats


use fn_formats::DebugFmt;

let debug = DebugFmt(|f| {
        .field("list", &DebugFmt(|f| f.debug_list().entries(&[1, 2, 3]).finish()))
        .field("set", &DebugFmt(|f| f.debug_set().entries(&[4, 5, 6]).finish()))

assert_eq!(format!("{:?}", debug), "StructName { list: [1, 2, 3], set: {4, 5, 6} }");


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Code of Conduct



fn-formats strictly follows Semantic Versioning 2.0.0 with the following exceptions:

  • The minor version will not reset to 0 on major version changes (except for v1).
    Consider it the global feature level.
  • The patch version will not reset to 0 on major or minor version changes (except for v0.1 and v1).
    Consider it the global patch level.

This includes the Rust version requirement specified above.
Earlier Rust versions may be compatible, but this can change with minor or patch releases.

Which versions are affected by features and patches can be determined from the respective headings in CHANGELOG.md.

No runtime deps