# loop_chain
Macro for writing nested Loop expressions
[](https://github.com/TaKO8Ki/loop_chain/actions) [](https://crates.io/crates/loop_chain) [](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;
loop_chain::loop_chain! {
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::>();
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::>();
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
- [if_chain](https://github.com/lambda-fairy/if_chain)