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{-# LANGUAGE TypeSynonymInstances, TemplateHaskell, QuasiQuotes, MultiParamTypeClasses, FlexibleInstances, DeriveDataTypeable, NamedFieldPuns, ScopedTypeVariables #-}
module Pnm where
import qualified Data.Char as Char
-- import Language.Pads.Padsc
import Control.Monad
_ws = one_or_more Char.isSpace
where one_or_more = undefined
ws, wsnl, whitechar :: RE
ws = REd "[ \t\n\r]+" " " -- whitespace
wsnl = let REd wplus _ = ws in REd wplus "\n" -- whitespace output as \n
whitechar = REd "[ \t\n\r]" "\n" -- one white character
[pads|
data PGMx a = PGM "P5" ws Header whitechar (Pixmap a)
data Header = Header -- fields should be separated by whitespace
{ width :: Int
ws , height :: Int
wsnl , constrain denominator :: Int
where <| 0 <= denominator && denominator < 65536 |>
}
data Pixmap a (h::Header) = Rows [Row a h | wsnl] length <| height h |>
data Row a (h::Header) = Pixels [a h | ws] length <| width h |>
newtype Greypix (h::Header) =
G constrain g::Int16 where <| 0 <= g && g <= denominator h |>
data PGM = PGMx Int16 Greypix
]
pgm file = do (rep, md) <- parseFile file
return rep
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