Debug.RecoverRTTI.Classify

Classification

classify :: a -> Either Closure (Classifier a)

Classify a value

Given a value of some unknown type a and a classifier Classifier a, it should be sound to coerce the value to the type indicated by the classifier.

This is also the reason not all values can be classified; in particular, we cannot classify values of unlifted types, as for these types coercion does not work (this would result in a ghc runtime crash).

User-defined types

data Classified a

Bundle a value with its classifier

Constructors

Classified (Classifier a) a

Instances

Show (Classified a)

Defined in Debug.RecoverRTTI.Classify

Methods

showsPrec :: Int -> Classified a -> ShowS

show :: Classified a -> String

showList :: [Classified a] -> ShowS

Show (Some Classified)

Defined in Debug.RecoverRTTI.Classify

Methods

showsPrec :: Int -> Some Classified -> ShowS

show :: Some Classified -> String

showList :: [Some Classified] -> ShowS

fromUserDefined :: UserDefined -> (String, [Some Classified])

Classify the arguments to the constructor

Additionally returns the constructor name itself.

Showing values

anythingToString :: forall a. a -> String

Show any value

This shows any value, as long as it's not unlifted. The result should be equal to show instances, with the following caveats:

• User-defined types (types not explicitly known to this library) with a custom Show instance will still be showable, but the result will be what the derived show instance would have done.
• Record field names are not known at runtime, so they are not shown.
• UNPACKed data is not visible to this library (if you compile with -O0 ghc will not unpack data, so that might be a workaround if necessary).

If classification fails, we show the actual closure.

canShowPrim :: PrimClassifier a -> Dict Show a

canShowClassified :: Classifier a -> Dict Show a

canShowClassified_ :: forall o. (forall a. o a -> Dict Show a) -> forall a. Classifier_ o a -> Dict Show a

Patterns for common shapes of Elems (exported for the tests)

pattern ElemK :: Classifier_ o a -> Elems o '[a]

pattern ElemU :: Elems o '[Void]

pattern ElemKK :: Classifier_ o a -> Classifier_ o b -> Elems o '[a, b]

pattern ElemUU :: Elems o '[Void, Void]

pattern ElemKU :: Classifier_ o a -> Elems o '[a, Void]

pattern ElemUK :: Classifier_ o b -> Elems o '[Void, b]

Orphan instances

Show UserDefined

Methods

showsPrec :: Int -> UserDefined -> ShowS

show :: UserDefined -> String

showList :: [UserDefined] -> ShowS