[Feature Request] Rank the hand for Omaha Hold'em

[azriel1rf]

I request the ranking an Omaha hands.

In Omaha Hold'em, four hole card are dealt for players and five cards are dealt on the board.
It's evaluated the best five-cards made from three of five cards on the board and two of four hole cards.

I'm also willing to contribute and send PR.
But, what is the best interface for that?

There are some choices.

Let's say AhAsKhKs in hole cards and QhJhTh9h8h on the board.

Example 1.

let best_card = Hand::new_from_str("AhKhQhJhTh").unwrap();

let hole_card = Hand::new_from_str("AhAsKhKs").unwrap();
let board = Hand::new_from_str("QhJhTh9h8h").unwrap();
let omaha_state = Omaha(board, hole_card);
assert_eq!(omaha_state.rank(), best_card.rank());

Example 2.

let best_card = Hand::new_from_str("AhKhQhJhTh").unwrap();

let hole_card = Hand::new_from_str("AhAsKhKs").unwrap();
let board = Hand::new_from_str("QhJhTh9h8h").unwrap();

assert_eq!(hole_card.rank_omaha(board), best_card.rank());

Example 3.

let best_card = Hand::new_from_str("AhKhQhJhTh").unwrap();

let hole_card = Hand::new_from_str("AhAsKhKs").unwrap();
let board = Hand::new_from_str("QhJhTh9h8h").unwrap();

assert_eq!(Rank::from_cards(Rule::Omaha, board, hole_card), best_card.rank());

[elliottneilclark]

Omaha would be a welcome addition for sure. My first thought would be to make it a ranker param.

let whole_hand = Hand::new_from_str("AhKhQhJhThQhJhTh9h8h").unwrap();
let rank = whole_hand.rank_omaha().unwrap();

Something like that. Hand is right now just a collection of cards that can be put together and ranked. Omaha has different requirements about what the possible combinations are.

What do you think?