# loop_chain Macro for writing nested Loop expressions [![github workflow status](https://img.shields.io/github/workflow/status/TaKO8Ki/loop_chain/CI/main)](https://github.com/TaKO8Ki/loop_chain/actions) [![crates](https://img.shields.io/crates/v/loop_chain.svg?logo=rust)](https://crates.io/crates/loop_chain) [![docs](https://img.shields.io/badge/docs-loop_chain-8da0cb?labelColor=555555&logo=rust)](https://docs.rs/loop_chain) [Usage](#Usage) | [Examples](examples) | [Docs](https://docs.rs/loop_chain)

Dependencies

toml [dependencies] loop_chain = "0.1.1"

Usage

For expression

rust fn main() { loop_chain::loop_chain! { for width in 0..10; for height in 0..10; then { println!("width: {}, height: {}", width, height); } } }

the generated code will be the following:

rust fn main() { for width in 0..10 { for height in 0..10 { println!("width: {}, height: {}", width, height); } } }

While expression

```rust fn main() { let mut foo = 0; loopchain::loopchain! { while foo < 3; foo += 1; for x in 0..10; then { println!("foo: {}, x: {}", foo, x); } } }

```

the generated code will be the following:

rust fn main() { let mut foo = 0; while foo < 3 { for x in 0..10 { println!("foo: {}, x: {}", foo, x); } } }

While let expression

rust fn main() { let mut foo = (0..10).collect::<Vec<u8>>(); loop_chain::loop_chain! { while let Some(v) = foo.pop(); for x in 0..10; then { println!("v: {}, x: {}", v, x); } } }

the generated code will be the following:

rust fn main() { let mut foo = (0..10).collect::<Vec<u8>>(); while let Some(v) = foo.pop() { for x in 0..10 { println!("v: {}, x: {}", v, x); } } }

Loop expression

rust fn main() { let mut foo = 0; loop_chain::loop_chain! { loop; foo += 1; if foo > 3 { break }; for x in 0..10; then { println!("foo: {}, x: {}", foo, x); } } }

the generated code will be the following:

rust fn main() { let mut foo = 0; loop { foo += 1; if foo > 3 { break }; for x in 0..10 { println!("foo: {}, x: {}", foo, x); } } }

Reference