https://github.com/kdy1/guard_let

https://github.com/kdy1/guard_let

Last synced: about 1 month ago
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• Host: GitHub
• URL: https://github.com/kdy1/guard_let
• Owner: kdy1
• Created: 2019-12-04T14:04:07.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2019-12-04T14:37:51.000Z (about 5 years ago)
• Last Synced: 2024-12-06T23:10:22.141Z (about 1 month ago)
• Language: Rust
• Size: 5.86 KB
• Stars: 7
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# guard_let

[![doc.rs](https://docs.rs/guard_let/badge.svg)](https://docs.rs/guard_let)

[![crates.io](https://img.shields.io/crates/v/guard_let.svg)](https://crates.io/crates/guard_let)

Guard let for rust. In rust, there exists a syntax sugar called if let.

But when it's nested, it make reading code really hard. `guard_let!` does inverse of lf let.

Execute code *below* guard only if guard matches,

and executes provided block if guard does not matches.

# Usage

```rust

use guard_let::guard_let;

enum Enum {

    A(String),

    B(usize),

    C(Struct),

}

struct Struct {

    foo: String,

}

fn eat_string(_: String) {}

#[guard_let]

fn simple_ident() {

    let v = Enum::A(String::from(""));

    guard_let!(v as Enum::A(s), {

        // Type of v is Enum at here.

        println!("v is not A: {:?}", v);

        return;

    });

    // Type of s is String

    eat_string(s)

}

#[guard_let]

fn pattern() {

    let v = Enum::A(String::from(""));

    guard_let!(v as Enum::C(Struct { foo }), {

        // Type of v is Enum at here.

        println!("v is not C: {:?}", v);

        return;

    });

    // Type of s is String

    eat_string(foo)

}

```

# License

MIT