mfmt 0.3.9

Meta formatter library
Documentation 
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# mfmt

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Meta formatter library in Rust.

`mfmt` is a language formatter library written in Rust inspired by `go fmt`. It's designed to be configuration-free and generous about styling. It simply focuses on aligning indentations.

This library is used in the following projects.

- [`schemat`, the Scheme formatter](https://github.com/raviqqe/schemat)
- [Pen programming language](https://github.com/pen-lang/pen)

## Install

```sh
cargo +nightly add mfmt
```

## Examples

```rust
#![feature(allocator_api)]

use indoc::indoc;
use mfmt::{Builder, format, FormatOptions, line};
use std::alloc::Global;

let builder = Builder::new(Global);
let mut string = String::new();

format(
    &builder.sequence([
        "{".into(),
        builder.indent(builder.sequence([line(), "foo".into(), line(), "bar".into()])),
        line(),
        "}".into(),
    ]),
    &mut string,
    FormatOptions::new(4),
)
.unwrap();

assert_eq!(
    string,
    indoc!(
        "
        {
            foo
            bar
        }
        "
    )
    .trim(),
);
```

## Technical notes

Unlike [the Wadler's algorithm][wadler] or some other formatters like [prettier](https://prettier.io/), `mfmt` does not search the best format given source codes. For example, we do not have any "group" combinator. Instead, we rather give a formatter information to reconstruct the "best" format that is available in the original source codes.

## References

- [A prettier printer by Philip Wadler][wadler]

## License

[The Unlicense](https://github.com/raviqqe/mfmt/blob/main/UNLICENSE)

[wadler]: https://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf