Adventure Day 16

Inspired by @jbrains doing (Langton's Ants)[https://en.wikipedia.org/wiki/Langton%27s_ant], I think I'll ponder the similar (turmites)[https://en.wikipedia.org/wiki/Turmite]

Why not!?

Repeating from wikipedia:

Specification

The following specification is specific to turmites on a two-dimensional square grid, the most studied type of turmite. Turmites on other grids can be specified in a similar fashion.

As with Langton's ant, turmites perform the following operations each timestep:

• turn on the spot (by some multiple of 90°)
• change the color of the square
• move forward one square.

As with Turing machines, the actions are specified by a state transition table listing the current internal state of the turmite and the color of the cell it is currently standing on.

+------------------+-------------------------------------------------------------------+
|                  |                          Current color                            |
|                  |---------------------------------+---------------------------------+
|                  |                 0               |                1                |
|                  |-------------+------+------------+-------------+------+------------+
|                  | Write color | Turn | Next state | Write color | Turn | Next state |
+--------------+---+-------------+------+------------+-------------+------+------------+
|              | 0 |      1      |  R   |      0     |      1      |   R  |      1     |
|Current state +---+-------------+------+------------+-------------+------+------------+
|              | 1 |      0      |  N   |      0     |      0      |   N  |      1     |
+--------------+---+-------------+------+------------+-------------+------+------------+

The direction to turn is one of L (90° left), R (90° right), N (no turn) and U (180° U-turn).

Implementation Notes

Day 8

• Okay, so a turmite needs to know it's current state: 0 or 1

Day 9

• The turmite needs to observe the color of the square it is on.

Note that I said "observe" and I did not imply that the color of the square is a property of the turmite.

Day 10

• Might not get to do anything tonight...

Day 11

• Let's execute a turn. I am not certain I grok the state table, but I think it says this:

  Scenario Outline: turmites eating squares Given my current state is When I land on a square Then I should move 90° And the square should change to <write_color> And my state should change to <next_state>

  Examples:
    | state | color | direction | write_color | next_state |
    |    0  |   0   |   right   |      1      |     0      |
    |    0  |   1   |   right   |      1      |     1      |
  

Day 12

• Nada

Day 13

• Let's execute a turn. I am not certain I grok the state table, but I think it says this:

  Scenario Outline: turmites eating squares Given my current state is When I land on a square Then I should move 90° And the square should change to <write_color> And my state should change to <next_state>

  Examples:
    | state | color | direction | write_color | next_state |
    |    0  |   0   |   right   |      1      |     0      |
    |    0  |   1   |   right   |      1      |     1      |
  

Day 14

• Still doing the turn...

Day 15

• CYA day

I like code coverage... So I installed my fave SimpleCov tool, and did the needful to the spec_helper.rb file.

Day 16

• So, when the turmite moves to a new square,
  • it translates,
  • it potentially faces a new direction
  • it can change it's own state
  • it can change the color of the square it is on (like leaving a turd behind?)