https://github.com/geky/cargo-what

Tells you what type things are
https://github.com/geky/cargo-what

Last synced: 1 day ago
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Tells you what type things are

• Host: GitHub
• URL: https://github.com/geky/cargo-what
• Owner: geky
• License: mit
• Created: 2020-10-17T15:01:39.000Z (about 4 years ago)
• Default Branch: master
• Last Pushed: 2020-10-19T06:49:28.000Z (about 4 years ago)
• Last Synced: 2024-10-21T01:34:45.914Z (about 1 month ago)
• Language: Rust
• Size: 22.5 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
What?

=====

Tells you what type things are.

This crate provides the `what!` macro. This is functionally similar to the

[`todo!`] macro, except that it also tells you type information.

``` rust

fn hello() -> Result<(), Box> {

    what!()

}

```

Just like [`todo!`], `what!` passes all type-checks and makes it easy to

write/build/test unfinished code. If it ever ends up in a compiled program,

attempted to execute a `what!` will panic.

The fun part happens when you run `cargo what`.

``` bash

$ cargo what

hole: expecting `std::result::Result<(), Box>`

 --> src/hello.rs

  |

2 |     what!()

  |     ^^^^^^^

```

Unfortunately, custom diagnostics aren't really available to Rust libraries,

requiring the extra command. `cargo what` can be installed with `cargo`:

``` bash

$ cargo install cargo-what

```

`cargo what` wraps `cargo build` to show the type-info of any `what!`s

you have in your code.

`what!` also accepts arguments and shows their types, which can be useful

for reducing the "unused variable" noise.

``` rust

fn hello(a: usize, b: usize) -> usize {

    let c = a..b;

    what!(a, b, c)

}

```

And with `cargo what`:

```bash

$ cargo what

hole: expecting `usize`

 --> src/hello.rs

  |

3 |     what!(a, b, c)

  |     ^^^^^^^^^^^^^^

  |

  = note: a is `usize`

  = note: b is `usize`

  = note: c is `std::ops::Range`

```

Emacs keybindings left as an exercise to the reader.

[`todo!`]: https://doc.rust-lang.org/std/macro.todo.html