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From: Hendrik Tews <tews@tcs.inf.tu-dresden.de>
To: Caml List <caml-list@inria.fr>
Subject: Re: [Caml-list] EQ hash tables?
Date: Wed, 12 Oct 2005 09:41:58 +0200	[thread overview]
Message-ID: <rlek6r41x5.fsf@ithif59.inf.tu-dresden.de> (raw)
In-Reply-To: <Pine.LNX.4.61.0510111652370.10250@katrin.cip.physik.uni-muenchen.de>

Thomas Fischbacher <Thomas.Fischbacher@Physik.Uni-Muenchen.DE> writes:

   Actually, this brings me to a question I wanted to ask for a long time: 
   while I never used this so far, I just assumed that OCaml does provide 
   hash tables where keys are compared w.r.t. "being the same" ('==' , that 
   is), rather than only hash tables where keys are compared for "being 
   equal" (say, '=').
   
Just look at hash.ml:

    let find h key =
      match h.data.((hash key) mod (Array.length h.data)) with
        Empty -> raise Not_found
      | Cons(k1, d1, rest1) ->
          if compare key k1 = 0 then d1 else
             ^^^^^^^^^^^^^^^^^^

So it's structual equality, which is the same as '=' modulo the
float nan issue.

Bye,

Hendrik


  reply	other threads:[~2005-10-12  7:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-10 13:42 [Caml-list] possible to define a type where = is forbidden ? yoann padioleau
2005-10-10 15:04 ` Thomas Fischbacher
2005-10-11 14:56   ` EQ hash tables? Thomas Fischbacher
2005-10-12  7:41     ` Hendrik Tews [this message]
2005-10-12  8:02     ` [Caml-list] " Xavier Leroy
2005-10-12 11:11       ` Thomas Fischbacher
2005-10-12 15:06         ` Xavier Leroy
2005-10-12 17:53           ` Thomas Fischbacher

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