https://github.com/thiskai/sac

A rust macro for constructing collections
https://github.com/thiskai/sac

Last synced: 8 days ago
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A rust macro for constructing collections

• Host: GitHub
• URL: https://github.com/thiskai/sac
• Owner: thisKai
• License: mit
• Created: 2018-04-27T15:28:21.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2019-08-16T16:44:47.000Z (over 5 years ago)
• Last Synced: 2024-10-13T01:48:01.052Z (about 1 month ago)
• Language: Rust
• Size: 26.4 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# sac

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

[![Documentation](https://docs.rs/sac/badge.svg)](https://docs.rs/sac)

![MIT License](https://img.shields.io/crates/l/sac.svg)

A rust macro that will construct an instance of any collection that implements [FromIterator](https://doc.rust-lang.org/std/iter/trait.FromIterator.html).

## Cargo.toml

```toml

[dependencies]

sac = "0.2"

```

## main.rs

```rust

#[macro_use]

extern crate sac;

fn main() {

    let vec: Vec<_> = sac![1, 2, 3, 4];

    assert_eq!(vec, vec![1, 2, 3, 4]);

}

```

No type annotations are needed if the compiler can infer the types:

```rust

struct VecWrapper(Vec);

let container = VecWrapper(sac![1, 2, 3, 4]);

```

Trailing commas are also supported:

```rust

let vec: Vec<_> = sac![

    1,

    2,

    3,

    4,

];

assert_eq!(vec, vec![1, 2, 3, 4]);

```

The macro can also construct maps (e.g. [HashMap](https://doc.rust-lang.org/std/collections/struct.HashMap.html)) with struct-like syntax:

```rust

use std::collections::HashMap;

let map_with_syntax_sugar: HashMap<_, _> = sac! {

    "foo": "bar",

    "marco": "polo",

};

let map_without_syntax_sugar: HashMap<_, _> = sac! [

    ("foo", "bar"),

    ("marco", "polo"),

];

assert_eq!(map_with_syntax_sugar, map_without_syntax_sugar);

```

Variables can be used as keys and values:

```rust

use std::collections::HashMap;

let key = "foo";

let value = "bar";

let map: HashMap<_, _> = sac! {

    key: value,

};

assert_eq!(map, sac! { "foo": "bar" });

```

To use expressions as keys, surround them with parentheses or braces:

```rust

use std::collections::HashMap;

let map: HashMap<_, _> = sac! {

    (1 + 1): "two",

    {2i32.pow(2)}: "four",

};

assert_eq!(map, sac! { 2: "two", 4: "four" });

```