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Experimental Hugs Libraries

• Trex This library supports TREX extensible records. These can only be used when Hugs is compiled with TREX support using the --enable-TREX configuration option. TREX documentation is included in this release.

• Dynamic This library provides support for dynamic typing. Adding further Typeable instances is left as an exercise for the ingenious reader.

    module Dynamic
  
    data Type = ...
    instance Eq   Type
    instance Show Type
    
    class Typeable a where typeOf :: a -> Type
    instance Typeable ()     
    instance Typeable Int    
    instance Typeable Integer
    instance Typeable Float  
    instance Typeable Double 
    instance Typeable Char   
    instance Typeable a => Typeable [a]
    instance (Typeable a, Typeable b) => Typeable (a -> b)
    instance (Typeable a, Typeable b) => Typeable (a,b)
    instance Typeable a => Typeable (IO a)
    
    data Dynamic
    instance Show Dynamic
    
    toDynamic   :: Typeable a => a -> Dynamic
    fromDynamic :: Typeable a => Dynamic -> Maybe a
    dynApply    :: Dynamic -> Dynamic -> Maybe Dynamic
  

  This should be regarded as an experimental feature that may change in future versions of Hugs.

• HugsInternals This library provides primitives for accessing Hugs internals; for example, they provide the means with which to implement simple error-recovery and debugging facilities in Haskell. These primitives should be regarded as an experimental feature and may not be supported in future versions of Hugs. They can only be used if Hugs was configured with the --enable-internal-prims flag.

• GenericPrint This library provides a "generic'' (or "polymorphic'') print function in Haskell, that works in essentially the same way as Hugs' builtin printer when the -u option is used. This library can only be used if Hugs was configured with the --enable-internal-prims flag.

• CVHAssert This library provides a simple implementation of Cordy Hall's assertions for performance debugging. These primitives are an experimental feature that may be removed in future versions of Hugs. They can only be used if Hugs was configured with the --enable-internal-prims flag.