Stable names/references may be what you need. http://research.microsoft.com/~simonpj/Papers/weak.htm Cheers -----Original Message----- From: Sergio Sebastián Giro [mailto:sergio@fceia.unr.edu.ar] Sent: Tuesday, 17 June, 2003 12:08 PM To: gilesb@cpsc.ucalgary.ca Cc: haskell@haskell.org Subject: Re: Hash in Haskell On Mon, 16 Jun 2003 gilesb@cpsc.ucalgary.ca wrote: Thanks anyway, but I want to maintain a set of elements of some (fixed) unknown type. In a hash table, I can see in O(1) aprox. if the element belongs or not to set.
Typically, such functions are often used to implement mappings from something (such as a String) to something else.
If that is what you want take a look at the type FiniteMap under the Data area of GHC and HUGS. It implements all the needed functionality without having to worry about creating a Hash for the keys.
If you want if for some other reason, you would typically need to define a class such as:
Class Hash where hash::a->Int
and then implement it on your desired types. Strings are ususally somewhat easy to create a unique has value, other types will, naturally, depend on what is in them.
On 16 Jun, Sergio Sebastián Giro wrote:
Hi, I need some function in Haskell to hash any value from any type to Int. I guess that such a function needs to be a primitive, but I don't found it in Hugs. Do you know how I can implement it or found it? Thanks Sergio _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
-- Brett G. Giles Grad Student, University of Calgary Formal Methods, Category Theory, Semantics of Programming http://www.cpsc.ucalgary.ca/~gilesb mailto:gilesb@cpsc.ucalgary.ca
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