The [cain!] macro is a macro that rewrites sequential Rust branch statements into nested branches.

This can be useful in cases where you want to have branches with different types that behave similarly, for example concrete types with a common trait, without having to use runtime trait objects like Box<dyn Trait>.

The disadvantage of this is that the amount of code grows exponentially relative to the number of sequential branches in the expanded code.

MSRV

The minimal supported Rust version for cain is 1.57.0 (December 2021).

Example

The code:

```nocompile fn foo(): Result { .. }

let a = cain! { let value = match foo() { Ok(n) => n, Err(b) => b, };

value.to_string() }; ```

Will be expanded by the cain! macro into the code:

```nocompile fn foo(): Result { .. }

let a = { match foo() { Ok(n) => { let value = n; n.tostring() }, Err(b) => { let value = b; b.tostring() } } }; ```