A gem for playing Conway's Game of Life and other Life-like cellular automata
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README.md

Lifelike

Gem Version Build Status Code Climate Test Coverage

Lifelike plays Conway's Game of Life by default but it can be used to simulate any Life-like cellular automata.

Rationale

This gem is inspired by the Global Day of Coderetreat where participants attempt to implement Conway's Game of Life under various constraints.

The goal of this implementation is to make the code as well-factored as possible, emphasizing the single responsibility principle, rather than as efficient as possible.

Installation

$ gem install lifelike

Usage

By default, Lifelike plays Conway's Game of Life.

It gets it initial state from standard input or a file and then prints the next generation:

$ echo "...\nooo\n..." > blinker
$ cat blinker
...
ooo
...
$ cat blinker | lifelike
.o.
.o.
.o.
$ lifelike blinker
.o.
.o.
.o.

Multiple generations

You can also provide a number of generations to simulate before printing:

$ echo "..o..\no.o..\n.oo..\n....." > glider
$ cat glider
..o..
o.o..
.oo..
.....
$ cat glider | lifelike -c 4
.....
...o.
.o.o.
..oo.

Alternate dead/alive characters

You don't have to use o and . to represent life and death. Lifelike will be smart and try to guess based on the input provided:

$ echo "000\n111\n000" | lifelike
010
010
010
$ echo "   \nXXX\n   " | lifelike
 X
 X
 X

You can use any combination of two of the following characters (which are in order here from what lifelike will consider more dead to more alive):

<space> _ . , o O 0 1 x * X # @

Game of Life variants

You can define the rules Lifelike will use with the -r flag.

By default, it uses the rules for Conway's Game of Life, which are B3/S23.

This format of specifying the rules means:

  • It takes 3 live neighbors for a cell to be born
  • It takes 2 or 3 live neighbors for a cell to stay alive

One interesting variant is called Seeds which has the rule B2/S, meaning:

  • It takes 2 live neighbors for a cell to be born
  • No cells ever survive

This is how you would make Lifelike play this variant:

$ echo ".......\n.......\n..oo..\n.......\n......." | lifelike -r "B2/S"
.......
..oo...
......
..oo...
.......
$ echo ".......\n.......\n..oo..\n.......\n......." | lifelike -r "B2/S" -c 2
..oo...
.......
.o..o.
.......
..oo...

Contributing

  1. Fork it ( https://github.com/mxhold/lifelike/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request