show function
Hamilton Richards
hrichrds at swbell.net
Tue Dec 2 22:18:01 EST 2003
At 10:05 PM -0500 12/2/03, rui yang wrote:
>I want to print a function which itself have some functions as it's parameters
>and will return some functions as the results, and I want to print out the
>result, does anyone knows how to define the instance declaration of show class
>to this function type?
[moving to Haskell Cafe]
The mechanics of such an instance definition are simple enough.
Letting F be your function type, this would do it:
> instance Show F where
> showsPrec f = ... some String ...
The hard question is what the result should be. Unlike the types
already in Show (such as Bool, Int, Char, etc.), there's no canonical
representation for functions (other than a complete list of
argument-result pairs, which would not be very useful).
Regards,
--Ham
--
------------------------------------------------------------------
Hamilton Richards, PhD Department of Computer Sciences
Senior Lecturer The University of Texas at Austin
512-471-9525 1 University Station C0500
Taylor Hall 5.138 Austin, Texas 78712-0233
ham at cs.utexas.edu hrichrds at swbell.net
------------------------------------------------------------------
More information about the Haskell-Cafe
mailing list