import "Prelude"
import "JavaBuiltin" as Java

@JavaType "org.simantics.scl.compiler.dynamic.SafeDynamic"
data SafeDynamic =
    @FieldNames [type_, value]
    SafeDynamic Type Dynamic

instance Show SafeDynamic where
    sb <+ SafeDynamic t v = sb << "SafeDynamic " <+ t

toSafeDynamic :: Typeable a => a -> SafeDynamic
toSafeDynamic val = SafeDynamic (typeOf val) (toDynamic val)

fromSafeDynamic :: Typeable a => SafeDynamic -> Maybe a
fromSafeDynamic (SafeDynamic type_ value) =
    if type_ == typeOfProxy (TypeProxy :: TypeProxy a)
    then Just (Java.unsafeCoerce value)
    else Nothing

forgetType :: SafeDynamic -> Dynamic
forgetType (SafeDynamic _ value) = value

typeOfSafeDynamic :: SafeDynamic -> Type
typeOfSafeDynamic (SafeDynamic t _) = t