module PDF.Content.Operator.GraphicState (
      Operator(..)
    , signature
  ) where

import PDF.Content.Operator.Common (Signature)
import PDF.Object (DirectObject(..))

data Operator =
  C_m | W_ | J | J_ | M | D_ | R_i | I_ | G_s -- general graphic state
  deriving (Bounded, Enum, Show)

signature :: [Signature Operator]
signature = [
      (C_m, \l -> case l of [_, _, _, _, _, _] -> True ; _ -> False)
    , (W_, \l -> case l of [_] -> True ; _ -> False)
    , (J, \l -> case l of [_] -> True ; _ -> False)
    , (J_, \l -> case l of [_] -> True ; _ -> False)
    , (M, \l -> case l of [_] -> True ; _ -> False)
    , (D_, \l -> case l of [_, _] -> True ; _ -> False)
    , (R_i, \l -> case l of [_] -> True ; _ -> False)
    , (I_, \l -> case l of [_] -> True ; _ -> False)
    , (G_s, \l -> case l of [NameObject _] -> True ; _ -> False)
  ]