Implementation of a basic in-memory stack in solidity.
The static sizing of the core array functions as the 'max length' of the stack. Not ideal for production purposes as-is without some optimization around the item size (set to uint256 in this example) and the max length (1024 in this example).
This implementation assumes you'd be using the Using A for B pattern in solidity for its use case.
contract MyContract {
using Stack for Stack1024;
// ...
}