Heap.Console.Value

Utilities for inspection of Haskell values.

Documentation

data FromValue box rep

Interpretation of Haskell value into representation r. Allows user to interpret inspection done by valueFromData or boxFromAny as needed.

Constructors

forall info. FromValue

Fields

• box :: box -> info -> rep

  Embeds information created about value together with it's box (wrapped original value itself) into final representation. It allows one to e.g. discard box if not used.

• list :: [rep] -> Maybe box -> info
• string :: [Either box Char] -> Maybe box -> info
• char :: Char -> info
• tuple :: [rep] -> info
• con :: Name -> [Word] -> [rep] -> info
• rec :: Name -> [(String, rep)] -> info
• fun :: info
• thunk :: info
• bytecode :: info
• byteArray :: Word -> [Word] -> info
• mutByteArray :: info
• mVar :: info
• mutVar :: rep -> info
• stmQueue :: info
• integral :: Integer -> PrettyType -> info
• floating :: Double -> PrettyType -> info
• int# :: Int -> info
• word# :: Word -> info
• int64# :: Int64 -> info
• word64# :: Word64 -> info
• addr# :: Int -> info
• float# :: Float -> info
• double# :: Double -> info
• other :: info
• depthLimit :: info

data Name

Runtime representation of Haskell identifier - can be both of type or value.

Constructors

Name

Fields

• namePkg :: String
• nameMod :: String
• nameId :: String
• nameFixity :: Fixity

Instances

Show Name

Defined in Heap.Console.Value

Methods

showsPrec :: Int -> Name -> ShowS

show :: Name -> String

showList :: [Name] -> ShowS

conName :: forall a. Data a => a -> Name

Name of given data constructor.

type PrettyType = String

Pretty representation of type at runtime - currently just String.

prettyType :: forall a. Typeable a => PrettyType

Shows type a as PrettyType.

data RepM a

Monad for inspecting representation of Haskell values - see runRepM.

Instances

Monad RepM

Defined in Heap.Console.Value

Methods

(>>=) :: RepM a -> (a -> RepM b) -> RepM b

(>>) :: RepM a -> RepM b -> RepM b

return :: a -> RepM a

Functor RepM

Defined in Heap.Console.Value

Methods

fmap :: (a -> b) -> RepM a -> RepM b

(<$) :: a -> RepM b -> RepM a

Applicative RepM

Defined in Heap.Console.Value

Methods

pure :: a -> RepM a

(<*>) :: RepM (a -> b) -> RepM a -> RepM b

liftA2 :: (a -> b -> c) -> RepM a -> RepM b -> RepM c

(*>) :: RepM a -> RepM b -> RepM b

(<*) :: RepM a -> RepM b -> RepM a

MonadIO RepM

Defined in Heap.Console.Value

Methods

liftIO :: IO a -> RepM a

Alternative RepM

Defined in Heap.Console.Value

Methods

empty :: RepM a

(<|>) :: RepM a -> RepM a -> RepM a

some :: RepM a -> RepM [a]

many :: RepM a -> RepM [a]

MonadReader RepOptions RepM

Defined in Heap.Console.Value

Methods

ask :: RepM RepOptions

local :: (RepOptions -> RepOptions) -> RepM a -> RepM a

reader :: (RepOptions -> a) -> RepM a

MonadError String RepM

Defined in Heap.Console.Value

Methods

throwError :: String -> RepM a

catchError :: RepM a -> (String -> RepM a) -> RepM a

data RepOptions

Options for representation inspection.

Constructors

RepOptions

Fields

• repDepth :: Natural

  Depth of inspection - guards against getting stuck in infinite structures.

• repStrict :: Bool

  Whether inspection should force thunks along the way.

• repTypes :: Bool

  Whether printed representations should contain type signatures in ambiguous places - used by prettyRep.

Instances

Show RepOptions

Defined in Heap.Console.Value

Methods

showsPrec :: Int -> RepOptions -> ShowS

show :: RepOptions -> String

showList :: [RepOptions] -> ShowS

MonadReader RepOptions RepM

Defined in Heap.Console.Value

Methods

ask :: RepM RepOptions

local :: (RepOptions -> RepOptions) -> RepM a -> RepM a

reader :: (RepOptions -> a) -> RepM a

runRepM :: RepM a -> RepOptions -> IO (Either String a)

Runs action that may make use of inspection of representation of Haskell values (e.g. using valueFromData or boxFromAny).

data Value

Lifted Haskell value together with it's Data instance.

Constructors

forall a.Data a => Value a

Instances

Show Value

Defined in Heap.Console.Value

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

valueFromData :: forall a r. Data a => FromValue Value r -> a -> RepM r

Inspects any value with Data instance using given interpretation. Prefer

data Box

An arbitrary Haskell value in a safe Box. The point is that even unevaluated thunks can safely be moved around inside the Box, and when required, e.g. in getBoxedClosureData, the function knows how far it has to evaluate the argument.

Constructors

Box (Any :: Type)

Instances

Show Box

Defined in GHC.Exts.Heap.Closures

Methods

showsPrec :: Int -> Box -> ShowS

show :: Box -> String

showList :: [Box] -> ShowS

asBox :: a -> Box

This takes an arbitrary value and puts it into a box. Note that calls like

asBox (head list)

will put the thunk "head list" into the box, not the element at the head of the list. For that, use careful case expressions:

case list of x:_ -> asBox x

boxFromAny :: forall r a. FromValue Box r -> a -> RepM r

Inspects any lifted value using given interpretation. This function can't recover some information compared to valueFromData - specifically, it never recovers record syntax and unpacked fields are only provided by their representation using Words.

index :: Either Box Value -> Bool -> [String] -> RepM (Either Box Value)

Indexes Haskell value using given "selection" - that is, Bool determining whether indexing should be always strict and list of indexes to walk through along the way. Valid indexes are:

• positive integer (e.g. 3) - position of element in list, tuple or other data constructor
• record field name (e.g. foo) - name of field in record (only works when given enough information - that is, with Value as input)

In case of Box, unpacked values are ignored while indexing.

prettyRep :: Either Box Value -> RepM String

Pretty-print given value. In case of Box, record syntax is never shown and (unpacked) fields may be shown as Word#s out of order.