Safe Haskell	Safe
Language	Haskell2010

Dynamic

Contents

Dynamic

Synopsis

data Dynamic where
- Dynamic :: Dynamic
toDyn :: Typeable a => a -> Dynamic
fromDynamic :: Typeable a => Dynamic -> Maybe a
dynApply :: Dynamic -> Dynamic -> Maybe Dynamic
dynTypeRep :: Dynamic -> SomeTypeRep

Dynamic

data Dynamic where #

A value of type Dynamic is an object encapsulated together with its type.

A Dynamic may only represent a monomorphic value; an attempt to create a value of type Dynamic from a polymorphically-typed expression will result in an ambiguity error (see toDyn).

Showing a value of type Dynamic returns a pretty-printed representation of the object's type; useful for debugging.

Constructors

Dynamic :: Dynamic

Instances

Show Dynamic	Since: base-2.1
Instance details Defined in Data.Dynamic Methods showsPrec :: Int -> Dynamic -> ShowS # show :: Dynamic -> String # showList :: [Dynamic] -> ShowS #
Exception Dynamic	Since: base-4.0.0.0
Instance details Defined in Data.Dynamic Methods toException :: Dynamic -> SomeException # fromException :: SomeException -> Maybe Dynamic # displayException :: Dynamic -> String #

toDyn :: Typeable a => a -> Dynamic #

Converts an arbitrary value into an object of type Dynamic.

The type of the object must be an instance of Typeable, which ensures that only monomorphically-typed objects may be converted to Dynamic. To convert a polymorphic object into Dynamic, give it a monomorphic type signature. For example:

   toDyn (id :: Int -> Int)

fromDynamic #

Arguments

:: Typeable a
=> Dynamic	the dynamically-typed object
-> Maybe a	returns: `Just a`, if the dynamically-typed object has the correct type (and `a` is its value), or `Nothing` otherwise.

Converts a Dynamic object back into an ordinary Haskell value of the correct type. See also fromDyn.

dynApply :: Dynamic -> Dynamic -> Maybe Dynamic #

dynTypeRep :: Dynamic -> SomeTypeRep #