| Portability | portable | 
|---|---|
| Stability | experimental | 
| Maintainer | libraries@haskell.org | 
| Safe Haskell | Trustworthy | 
Data.Dynamic
Description
The Dynamic interface provides basic support for dynamic types.
Operations for injecting values of arbitrary type into a dynamically typed value, Dynamic, are provided, together with operations for converting dynamic values into a concrete (monomorphic) type.
Documentation
module Data.Typeable
The Dynamic type
data Dynamic
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.
Converting to and from Dynamic
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)
Arguments
| :: Typeable a | |
| => Dynamic | the dynamically-typed object | 
| -> a | a default value | 
| -> a | returns: the value of the first argument, if it has the correct type, otherwise the value of the second argument. | 
Converts a Dynamic object back into an ordinary Haskell value of
 the correct type.  See also fromDynamic.
Applying functions of dynamic type
dynTypeRep :: Dynamic -> TypeRep