Commit | Line | Data |
---|---|---|
7f968603 SK |
1 | -module(life). |
2 | ||
3 | -export([bang/1]). | |
4 | ||
5 | ||
6 | -define(CHAR_DEAD, 32). % " " | |
7 | -define(CHAR_ALIVE, 111). % "o" | |
8 | -define(INTERVAL, 100). | |
9 | ||
10 | ||
11 | %% ============================================================================ | |
12 | %% API | |
13 | %% ============================================================================ | |
14 | ||
15 | bang(Args) -> | |
16 | [X, Y] = [atom_to_integer(A) || A <- Args], | |
17 | Board = init_board(X, Y), | |
18 | life_loop(Board). | |
19 | ||
20 | ||
21 | %% ============================================================================ | |
22 | %% Internal | |
23 | %% ============================================================================ | |
24 | ||
25 | life_loop(Board) -> | |
26 | ok = do_print_board(Board), | |
27 | timer:sleep(?INTERVAL), | |
28 | life_loop(next_generation(Board)). | |
29 | ||
30 | ||
31 | do_print_board(Board) -> | |
32 | CharLists = array:to_list( | |
33 | array:map( | |
34 | fun(_, Row) -> | |
35 | array:to_list( | |
36 | array:map( | |
37 | fun(_, State) -> | |
38 | state_to_char(State) | |
39 | end, | |
40 | Row | |
41 | ) | |
42 | ) | |
43 | end, | |
44 | Board | |
45 | ) | |
46 | ), | |
47 | ||
48 | ok = lists:foreach( | |
49 | fun(CharList) -> | |
50 | ok = io:format("~s~n", [CharList]) | |
51 | end, | |
52 | CharLists | |
53 | ). | |
54 | ||
55 | ||
56 | state_to_char(0) -> ?CHAR_DEAD; | |
57 | state_to_char(1) -> ?CHAR_ALIVE. | |
58 | ||
59 | ||
60 | next_generation(Board) -> | |
61 | H = array:size(Board), | |
62 | W = array:size(array:get(0, Board)), | |
63 | ||
64 | array:map( | |
65 | fun(Y, Row) -> | |
66 | array:map( | |
67 | fun(X, State) -> | |
68 | Neighbors = filter_offsides(H, W, neighbors(X, Y)), | |
69 | States = neighbor_states(Board, Neighbors), | |
70 | LiveNeighbors = lists:sum(States), | |
71 | new_state(State, LiveNeighbors) | |
72 | end, | |
73 | Row | |
74 | ) | |
75 | end, | |
76 | Board | |
77 | ). | |
78 | ||
79 | ||
80 | new_state(1, LiveNeighbors) when LiveNeighbors < 2 -> 0; | |
81 | new_state(1, LiveNeighbors) when LiveNeighbors < 4 -> 1; | |
82 | new_state(1, LiveNeighbors) when LiveNeighbors > 3 -> 0; | |
83 | new_state(0, LiveNeighbors) when LiveNeighbors =:= 3 -> 1; | |
84 | new_state(State, _LiveNeighbors) -> State. | |
85 | ||
86 | ||
87 | neighbor_states(Board, Neighbors) -> | |
88 | [array:get(X, array:get(Y, Board)) || {X, Y} <- Neighbors]. | |
89 | ||
90 | ||
91 | filter_offsides(H, W, Coordinates) -> | |
92 | [{X, Y} || {X, Y} <- Coordinates, is_onside(X, Y, H, W)]. | |
93 | ||
94 | ||
95 | is_onside(X, Y, H, W) when (X >= 0) and (Y >= 0) and (X < W) and (Y < H) -> true; | |
96 | is_onside(_, _, _, _) -> false. | |
97 | ||
98 | ||
99 | neighbors(X, Y) -> | |
100 | [{X + OffX, Y + OffY} || {OffX, OffY} <- offsets()]. | |
101 | ||
102 | ||
103 | offsets() -> | |
104 | [offset(D) || D <- directions()]. | |
105 | ||
106 | ||
107 | offset('N') -> { 0, -1}; | |
108 | offset('NE') -> { 1, -1}; | |
109 | offset('E') -> { 1, 0}; | |
110 | offset('SE') -> { 1, 1}; | |
111 | offset('S') -> { 0, 1}; | |
112 | offset('SW') -> {-1, 1}; | |
113 | offset('W') -> {-1, 0}; | |
114 | offset('NW') -> {-1, -1}. | |
115 | ||
116 | ||
117 | directions() -> | |
118 | ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW']. | |
119 | ||
120 | ||
121 | init_board(X, Y) -> | |
122 | array:map(fun(_, _) -> init_row(X) end, array:new(Y)). | |
123 | ||
124 | ||
125 | init_row(X) -> | |
126 | array:map(fun(_, _) -> init_cell_state() end, array:new(X)). | |
127 | ||
128 | ||
129 | init_cell_state() -> | |
130 | crypto:rand_uniform(0, 2). | |
131 | ||
132 | ||
133 | atom_to_integer(Atom) -> | |
134 | list_to_integer(atom_to_list(Atom)). |