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    1 {-# LANGUAGE DeriveGeneric, DeriveDataTypeable, DeriveFunctor, DeriveTraversable, DeriveFoldable #-}
    2 
    3 module Conjure.Language.Expression.Op.Flatten where
    4 
    5 import Conjure.Prelude
    6 import Conjure.Language.Expression.Op.Internal.Common
    7 
    8 import qualified Data.Aeson as JSON             -- aeson
    9 import qualified Data.Aeson.KeyMap as KM
   10 
   11 import qualified Data.Vector as V               -- vector
   12 
   13 
   14 data OpFlatten x = OpFlatten (Maybe Int) x
   15     deriving (Eq, Ord, Show, Data, Functor, Traversable, Foldable, Typeable, Generic)
   16 
   17 instance Serialize x => Serialize (OpFlatten x)
   18 instance Hashable  x => Hashable  (OpFlatten x)
   19 instance ToJSON    x => ToJSON    (OpFlatten x) where toJSON = genericToJSON jsonOptions
   20 instance FromJSON  x => FromJSON  (OpFlatten x) where parseJSON = genericParseJSON jsonOptions
   21 
   22 instance (TypeOf x, Pretty x) => TypeOf (OpFlatten x) where
   23     typeOf p@(OpFlatten Nothing m) = do
   24         let flattenType (TypeList inner) = flattenType inner
   25             flattenType (TypeMatrix _ inner) = flattenType inner
   26             flattenType ty = ty
   27         ty <- typeOf m
   28         case ty of
   29             TypeList n -> return (TypeList (flattenType n))
   30             TypeMatrix _ n -> return (TypeList (flattenType n))
   31             _ -> raiseTypeError $ vcat [ pretty p
   32                                        , "The argument has type:" <+> pretty ty
   33                                        ]
   34     typeOf p@(OpFlatten (Just n) m) = do
   35         let flattenType lvl ty | lvl < 0 = return ty
   36             flattenType lvl (TypeList inner) = flattenType (lvl-1) inner
   37             flattenType lvl (TypeMatrix _ inner) = flattenType (lvl-1) inner
   38             flattenType _ _ = raiseTypeError $ vcat [pretty p, "Cannot flatten" <+> pretty n <+> "levels."]
   39         ty <- typeOf m
   40         TypeList <$> flattenType n ty
   41 
   42 instance SimplifyOp OpFlatten x where
   43     simplifyOp _ = na "simplifyOp{OpFlatten}"
   44 
   45 instance Pretty x => Pretty (OpFlatten x) where
   46     prettyPrec _ (OpFlatten Nothing  m) = "flatten" <> prParens (pretty m)
   47     prettyPrec _ (OpFlatten (Just n) m) = "flatten" <> prettyList prParens "," [pretty n, pretty m]
   48 
   49 instance VarSymBreakingDescription x => VarSymBreakingDescription (OpFlatten x) where
   50     varSymBreakingDescription (OpFlatten n m) = JSON.Object $ KM.fromList
   51         [ ("type", JSON.String "OpFlatten")
   52         , ("children", JSON.Array $ V.fromList
   53             [ toJSON n
   54             , varSymBreakingDescription m
   55             ])
   56         ]