27 lines
820 B
Haskell
27 lines
820 B
Haskell
|
module GOL.Rule where
|
||
|
|
|
||
|
|
-- | The rule of a Conway's Game of Life simulation
|
||
|
|
-- describes how a cell changes based on its surrounding
|
||
|
|
-- cells. The official GOL uses one standard rule, but
|
||
|
|
-- this engine allows for an arbitrary rule to be applied.
|
||
|
|
--
|
||
|
|
-- A rule consists of two predicates that take a value
|
||
|
|
-- in the range [0..8], the count of alive cells neighboring
|
||
|
|
-- the current cell, and returns whether that cell will be
|
||
|
|
-- alive in the next generation.
|
||
|
|
data Rule = Rule
|
||
|
|
{
|
||
|
|
-- | A predicate deciding if an alive cell
|
||
|
|
-- will be alive in the next generation.
|
||
|
|
survive :: Int -> Bool,
|
||
|
|
-- | A predicate deciding if a dead cell
|
||
|
|
-- will be alive in the next generation.
|
||
|
|
birth :: Int -> Bool
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
-- | The standard GOL rule (S23/B3).
|
||
|
|
standardRule :: Rule
|
||
|
|
standardRule = Rule (`elem` [2,3]) (== 3)
|
||
|
|
|