module Satchmo.Relation.Data
( Relation, relation, build
, bounds, (!), indices, assocs
, table
)
where
import Satchmo.Code
import Satchmo.Boolean
import qualified Data.Array as A
import Data.Array hiding ( bounds, (!), indices, assocs )
import Control.Monad ( guard )
data Relation a b = Relation ( Array (a,b) Boolean )
relation :: ( Ix a, Ix b, MonadSAT m )
=> ((a,b),(a,b)) -> m ( Relation a b )
relation bnd = do
pairs <- sequence $ do
p <- range bnd
return $ do
x <- boolean
return ( p, x )
return $ build bnd pairs
build :: ( Ix a, Ix b )
=> ((a,b),(a,b))
-> [ ((a,b), Boolean ) ]
-> Relation a b
build bnd pairs = Relation $ array bnd pairs
bounds :: (Ix a, Ix b) => Relation a b -> ((a,b),(a,b))
bounds ( Relation r ) = A.bounds r
indices ( Relation r ) = A.indices r
assocs ( Relation r ) = A.assocs r
Relation r ! p = r A.! p
instance (Ix a, Ix b) => Decode ( Relation a b ) ( Array (a,b) Bool ) where
decode ( Relation r ) = do
decode r
table :: (Enum a, Ix a, Enum b, Ix b)
=> Array (a,b) Bool -> String
table r = unlines $ do
let ((a,b),(c,d)) = A.bounds r
x <- [ a .. c ]
return $ unwords $ do
y <- [ b .. d ]
return $ if r A.! (x,y) then "*" else "."