A macro for if / if let chains until [RFC 2497] is implemented.
```rust use iff::iff;
fn go(var: Option
fn main() { go(None); go(Some(vec![])); go(Some(vec![0])); go(Some(vec![0, 1])); go(Some(vec![0, 1, 2])); } ```
Output:
None
Some([])
Some([0])
Some([0, 1]) => ok
Some([0, 1, 2])