| Copyright | (c) The University of Glasgow 2001 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | [email protected] |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
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.
module Data.Typeable
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.
toDyn :: Typeable a => a -> Dynamic Source
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)
| :: 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.
| :: Typeable a | |
| => Dynamic | the dynamically-typed object |
| -> Maybe a | returns: |
Converts a Dynamic object back into an ordinary Haskell value of the correct type. See also fromDyn.
dynApply :: Dynamic -> Dynamic -> Maybe Dynamic Source
dynApp :: Dynamic -> Dynamic -> Dynamic Source
dynTypeRep :: Dynamic -> TypeRep Source
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.0.1/docs/html/libraries/base-4.9.0.0/Data-Dynamic.html