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modifying hash tables
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Date: -- (:)
From: Sam Steingold <sds@g...>
Subject: Re: modifying hash tables
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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?

in case you wondered why I think my code is reasonable:
http://www.lisp.org/HyperSpec/Body/sec_3-6.html

Hash-table traversal

    For hash table traversal operations, new elements may not be added
or deleted except that the element corresponding to the current hash key
may be changed or removed.



(yes, I know OCaml is NOT Common Lisp).


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