baba

Simplified implementation of Baba Is You, fo the purpose of a code golfing challenge. This implementation is limited to the following parts of the game:

• 4 possible entities: Baba, Wall, Flag, Rock (uppercase)
• 4 corresponding nouns (lowercase)
• 3 properties: push, win and the pronoun you
• Operator is

Overall this gives 12 possible grid states + empty (13 overall).

Rules

As compared to the original, the following interactions are simplified in this version:

• Entities cannot overlap. Effectively everything is stop. This should prevent the game from becoming too broken and makes programming easier. While still allowing for interesting things to happen.
• No idle nor undo actions.

The following, however, are supposed to work:

• Noun is Noun. Something like baba is wall, for example.
• NounA is NounA overruling the behaviors of NounA is NounB. For example if wall is wall, wall cannot be baba. The rule wall is baba can exist but it does nothing.
• Text is implicitly push.

Gameplay

The game is played by providing a sequence of actions. The allowed actions are up, down, left and right. The game is won when 1) an entity which is you attempts to enter (since everything is stop) the square with another entity which is win , or 2) the entity which is you is also win. Note, that if a flag which is push and win is pushed, you don't win, unless it is pushed against a wall, in which case it is stuck and you do in fact win.

The order of operation of each turn is as follows:

• Search the grid for all the current rules
• Parse the rules into behaviors and swaps
• Apply all the swaps to the grid
• Perform an action for the turn according to the behaviors

This is done for each of the steps in a sequence. The game stops if the win condition is reached at any point, or if further play is unnecessary because nothing is you (effectively a loss).

Examples

The gifs in this section have been generated with animate\animate.py and the accompanying IPython notebook.

Flag is already win, so all baba needs to do is to attempt to walk on it. >>>> wouldn't work because in this version everything is stop. Hence >>^>>V:

In a similar manner, fastest loss can be achieved by breaking the Baba is You rule with <^<V:

Winning with rocks

Somewhat more creative win can be achieved by making Rock if Baba and walking onto the flag. This can be done with <^^^<<V^>>VV<<>>:

Similarly, Rock can be made into You with <^^^<<V^<<VV>><<^>><<. Note that the last few moves could not be made to the right because Baba, who is also You would have broken the Rock is You rule after one step.

The sequence <VVV<^<^>V>^^V<<<<^^^>^>>>>VVV<^>>> makes rock is win rule instead:

If the rock is push and rock is win you have to push the rock into a stuck position to actually win with it:

Swap order

Swaps are applied in alphabetic order, sorted by first and then second noun. They are applied to a copy of the grid., but only once per item. The following examples illustrate:

and

Two swap rules come into existence simultaneously: rock is baba and rock is flag. The former is applied first. Then, the latter is not applied because a rule has already been applied to rock. I think (but I'm not 100% sure) that the same behavior would result if all the swaps were to be applied to the grid sorted in the reverse alphabetic order by the second noun.

The above sequences of moves are: <^<<<<V>>^<<^^>>V^<<VV>>^><V><V><<<VVV>^^<^>>V>^^<^>VVV>VV<<^^^<^>V>^<^>><<V<<^>>>>>V<^<VV<<, and <^<<<<V>>^<<^^>>VV<V>V>>VV<<^V<<^>^^^<^>^>VV>V<V<V>^^>V>V>>>^^<<.

This type of behaviour is different to the original Baba is You game, since only one symbol can exist in a tile.

ToDo's

• Actually meet the scope
• Write a nice renderer of a game (make a gif of it, for example)
• Write an tiny codegolf version. Given a sequence of moves, does it win on a standardised level? For this it might be best to make a smaller level with just Baba, Flag and Rock. Maybe something like that(?):

. . . . . . . . . . . . .
. r i p . . . . R R R . .
. . . . . . . R . . . R .
. b i y . B . R . F . R .
. . . . . . . R . . . R .
. f i n . . . . R R R . .
. . . . . . . . . . . . .

Also

• Actually put things into classes?
• Hook up coveralls?