never executed always true always false

    1 module ElmFormat.AST.PublicAST.Reference (Reference(..),mkReference,toRef) where
    2 
    3 import ElmFormat.AST.PublicAST.Core
    4 
    5 
    6 data Reference
    7     = ExternalReference
    8         { module_ :: ModuleName
    9         , identifier :: Ref ()
   10         }
   11     | VariableReference
   12         { name :: Ref ()
   13         }
   14 
   15 mkReference :: Ref [UppercaseIdentifier] -> Reference
   16 mkReference = \case
   17     VarRef [] var ->
   18         VariableReference $ VarRef () var
   19 
   20     VarRef namespace var ->
   21         ExternalReference
   22             (ModuleName namespace)
   23             (VarRef () var)
   24 
   25     TagRef [] tag ->
   26         VariableReference $ TagRef () tag
   27 
   28     TagRef namespace tag ->
   29         ExternalReference
   30             (ModuleName namespace)
   31             (TagRef () tag)
   32 
   33     OpRef sym ->
   34         VariableReference $ OpRef sym
   35 
   36 toRef :: Reference -> Ref [UppercaseIdentifier]
   37 toRef = \case
   38     VariableReference (VarRef () var) ->
   39         VarRef [] var
   40 
   41     VariableReference (TagRef () tag) ->
   42         TagRef [] tag
   43 
   44     VariableReference (OpRef sym) ->
   45         OpRef sym
   46 
   47     ExternalReference (ModuleName mod) (VarRef () var) ->
   48         VarRef mod var
   49 
   50     ExternalReference (ModuleName mod) (TagRef () tag) ->
   51         TagRef mod tag
   52 
   53     ExternalReference (ModuleName mod) (OpRef sym) ->
   54         OpRef sym
   55 
   56 
   57 instance ToJSON Reference where
   58     toJSON = undefined
   59     toEncoding = pairs . toPairs
   60 
   61 instance ToPairs Reference where
   62     toPairs = \case
   63         ExternalReference module_ identifier ->
   64             mconcat
   65                 [ type_ "ExternalReference"
   66                 , "module" .= module_
   67                 , "identifier" .= identifier
   68                 ]
   69 
   70         VariableReference name ->
   71             mconcat
   72                 [ type_ "VariableReference"
   73                 , "name" .= name
   74                 ]
   75 
   76 instance FromJSON Reference where
   77     parseJSON = withObject "Reference" $ \obj -> do
   78         tag <- obj .: "tag"
   79         case tag of
   80             "VariableReference" -> do
   81                 VariableReference
   82                     <$> obj .: "name"
   83 
   84             "ExternalReference" ->
   85                 ExternalReference
   86                     <$> obj .: "module"
   87                     <*> obj .: "identifier"
   88 
   89             _ ->
   90                 fail ("unexpected Reference tag: " <> tag)