# Stack trait
[](https://crates.io/crates/stack-trait)
[](https://crates.io/crates/stack-trait)
[](https://docs.rs/stack-trait)
[](https://crates.io/crates/stack-trait)
[](https://deps.rs/repo/github/JohnScience/stack-trait)
Stack trait with entry API for the LIFO element.
## Example
```rust
use stack_trait::{Stack, LIFOEntry};
// types are written explicitly for clarity
fn main() {
let mut stack: Vec<i32> = vec![1, 2, 3];
// When we push to the stack, we can get an "entry" object
// that corresponds to the pushed element.
let mut entry: LIFOEntry<'_, Vec<i32>> = stack.lifo_push(4);
// This object can be dereferenced to get the shared
// reference to the element.
assert_eq!(*entry, 4);
// We also can dereference LIFO entry mutably to get
// the mutable reference to the element and change the
// element.
*entry = 5;
// After this we can dereference it immutably again.
assert_eq!(*entry, 5);
// However, we must drop the entry before we can use
// the stack again.
drop(entry);
assert_eq!(stack, vec![1, 2, 3, 5]);
// In this case, we could be bold to use
// `.lifo_unchecked()` unsafe method but the
// boundary check at this unwrap should be
// optimized out by the compiler.
let entry = stack.lifo().unwrap();
// In addition, we can pop the element from the stack
assert_eq!(entry.pop(), 5);
assert_eq!(stack, vec![1, 2, 3]);
}
```
As demonstrated above, `LIFOEntry<'a,C>` can be coverted to `&'a C`, `&'a mut C` or even `C` at our discretion.
## Notes
At the point of writing, this trait is implemented only for `Vec<T>`. However, having this trait implemented for other types, such as `ArrayVec<T>` is welcome.