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modifying hash tables
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Date: -- (:)
From: Jon Harrop <jon@f...>
Subject: Re: [Caml-list] modifying hash tables
On Wednesday 18 July 2007 16:27:45 Sam Steingold wrote:
> I want to modify the _current_ datum in Hashtable.iter, e.g., increment
> a count. Is this code valid?
> Hashtable.iter ht ~f:(fun ~key ~data ->
>   Hashtable.replace ht ~key ~data:(data+1))
> (it appears to work, but I was told that "it is not guaranteed to work",
> i.e., the documentation does not promise that).
> If the above code is wrong, what is TRT?

I would store "int ref"s in the hash table and use "incr".

Dr Jon D Harrop, Flying Frog Consultancy Ltd.
OCaml for Scientists