never executed always true always false

    1 {-# LANGUAGE DeriveGeneric, DeriveDataTypeable, DeriveFunctor, DeriveTraversable, DeriveFoldable #-}
    2 
    3 module Conjure.Language.Expression.Op.Substring 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 OpSubstring x = OpSubstring x x
   15     deriving (Eq, Ord, Show, Data, Functor, Traversable, Foldable, Typeable, Generic)
   16 
   17 instance Serialize x => Serialize (OpSubstring x)
   18 instance Hashable  x => Hashable  (OpSubstring x)
   19 instance ToJSON    x => ToJSON    (OpSubstring x) where toJSON = genericToJSON jsonOptions
   20 instance FromJSON  x => FromJSON  (OpSubstring x) where parseJSON = genericParseJSON jsonOptions
   21 
   22 instance BinaryOperator (OpSubstring x) where
   23     opLexeme _ = L_substring
   24 
   25 instance (TypeOf x, Pretty x) => TypeOf (OpSubstring x) where
   26     typeOf p@(OpSubstring a b) = do
   27         tya <- typeOf a
   28         tyb <- typeOf b
   29         case (tya, tyb) of
   30             (TypeSequence{}, TypeSequence{}) -> return TypeBool
   31             _ -> raiseTypeError $ vcat [ pretty p
   32                                        , "Unexpected types for operands:"
   33                                        , " - " <> pretty tya
   34                                        , " - " <> pretty tyb
   35                                        ]
   36 
   37 instance SimplifyOp OpSubstring x where
   38     simplifyOp _ = na "simplifyOp{OpSubstring}"
   39 
   40 instance Pretty x => Pretty (OpSubstring x) where
   41     prettyPrec prec op@(OpSubstring a b) = prettyPrecBinOp prec [op] a b
   42 
   43 instance VarSymBreakingDescription x => VarSymBreakingDescription (OpSubstring x) where
   44     varSymBreakingDescription (OpSubstring a b) = JSON.Object $ KM.fromList
   45         [ ("type", JSON.String "OpSubstring")
   46         , ("children", JSON.Array $ V.fromList
   47             [ varSymBreakingDescription a
   48             , varSymBreakingDescription b
   49             ])
   50         ]