https://github.com/oxeu/kotlike

A Rust macro to modify the question mark operator's behavior just like Kotlin's
https://github.com/oxeu/kotlike

crates macro macros-rust rust

Last synced: about 4 hours ago
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A Rust macro to modify the question mark operator's behavior just like Kotlin's

• Host: GitHub
• URL: https://github.com/oxeu/kotlike
• Owner: OXeu
• License: apache-2.0
• Created: 2024-01-07T15:09:31.000Z (10 months ago)
• Default Branch: master
• Last Pushed: 2024-01-07T15:47:38.000Z (10 months ago)
• Last Synced: 2024-10-12T17:43:03.994Z (24 days ago)
• Topics: crates, macro, macros-rust, rust
• Language: Rust
• Homepage:
• Size: 10.7 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
Kotlike

A Rust macro to modify the question mark operator's behavior just like Kotlin's




With it, you can easily pick out the value wrapped in numberless `Option` and `Result`.

Furthermore, it won't break down your control flow. You can continue your work even you got a `None` or `Err` (All the unexpected value will turn to `None`)

It means:

```rust

fn do_something() {

    let value: Option = wrapped_value?.something_return_option()?.something_return_result()?.value;

}

```

would works fine! Just as Kotlin's style.

And you don't need to worry about what `Err` it would throw!

# How it Works

**Usage**

```rust

#[kotlike]

fn main() {

    let a = "Hello".to_string();

    

    let c = File::create("test.txt")?.write_all(a.as_bytes())?.clone();

    

    let mut b: String = String::new();

    

    let len = File::open("test.txt")?.read_to_string(&mut b)?.clone();

    

    println!("Hello, {:?}({:?})!", b,len);

}

```

**Expand the macro would look like**:

```rust

fn main() {

  let a = "Hello".to_string();

    

  let c: Option<()> = File::create("test.txt")

      .map_or(None, |mut v| {

          v.write_all(a.as_bytes())

              .map_or(None, |mut v| Some(v.clone()))

      });

    

  let mut b: String = String::new();

    

  let len: Option = File::open("test.txt")

      .map_or(None, |mut v|{

          v.read_to_string(&mut b)

              .map_or(None, |mut v| Some(v.clone()))

      });

    println!("Hello, {:?}({:?})!", b,len);

}

```

Above example is just showing how it works. Don't focus too much on what stupid code does.

# LICENSE

[Apache LICENSE 2.0](LICENSE)