Building the Wall

The first step before the game can be played is that the four "walls" need to be built. Physically, this involves shuffling the deck and stacking the tiles into four rows of a certain length and 2 tiles tall.

In code, this is broken up into a few steps:

Determine the size of the deck

Depending on the variation, some of the "suits" are excluded. In the standard variation, there are the following tile quantities:

Suit	Examples	Quantity of Each Tile
Character	🀉🀍🀏	4 per number
Bamboo	🀐🀑🀗	4 per number
Circle	🀙🀝🀟	4 per number
Winds	🀀🀁🀂🀃	4 of each
Dragons	🀄🀅🀆	4 of each
Flowers/Seasons	🀢🀤🀦🀩	1 of each

Create and shuffle the deck

For the standard deck, there's a single argument constructor that automatically creates a deck with the correct number of tiles.

using MahjongTiles: TilePile

deck = TilePile(:standard)

🀇🀇🀇🀇🀈🀈🀈🀈🀉🀉🀉🀉🀊🀊🀊🀊🀋🀋🀋🀋🀌🀌🀌🀌🀍🀍🀍🀍🀎🀎🀎🀎🀏🀏🀏🀏🀐🀐🀐🀐🀑🀑🀑🀑🀒🀒🀒🀒🀓🀓🀓🀓🀔🀔🀔🀔🀕🀕🀕🀕🀖🀖🀖🀖🀗🀗🀗🀗🀘🀘🀘🀘🀙🀙🀙🀙🀚🀚🀚🀚🀛🀛🀛🀛🀜🀜🀜🀜🀝🀝🀝🀝🀞🀞🀞🀞🀟🀟🀟🀟🀠🀠🀠🀠🀡🀡🀡🀡🀀🀀🀀🀀🀁🀁🀁🀁🀂🀂🀂🀂🀃🀃🀃🀃🀄🀄🀄🀄🀅🀅🀅🀅🀆🀆🀆🀆🀢🀣🀤🀥🀦🀧🀨🀩

Then, we shuffle the deck.

using Random

shuffle!(deck)

🀥🀂🀜🀌🀘🀆🀙🀉🀚🀈🀅🀞🀂🀞🀏🀗🀏🀑🀧🀝🀛🀃🀏🀕🀕🀈🀟🀋🀖🀟🀊🀤🀃🀛🀎🀀🀒🀒🀠🀀🀐🀕🀅🀎🀙🀙🀙🀝🀣🀚🀇🀠🀈🀉🀊🀜🀕🀅🀋🀏🀃🀡🀇🀉🀁🀆🀊🀖🀁🀡🀐🀒🀗🀨🀆🀎🀛🀐🀍🀔🀛🀜🀘🀝🀌🀓🀒🀠🀄🀔🀈🀅🀄🀑🀉🀓🀍🀖🀁🀟🀐🀑🀦🀄🀩🀌🀇🀋🀗🀄🀞🀓🀆🀔🀔🀖🀢🀋🀚🀌🀀🀀🀓🀡🀊🀝🀠🀡🀑🀂🀂🀟🀗🀚🀃🀘🀜🀇🀁🀍🀞🀘🀎🀍

In a physical game of Mahjong, dice are rolled to determine where to start distributing tiles. However, this is mostly an anti-cheat measure and doesn't meaningfully affect the game itself. We could roll some dice and then use circshift! to adjust the deck, but that's mostly for show (e.g. in a GUI implementation).