R5RS doesn't provide bit operations or bit vectors. R6RS provides bit operations but not bit vectors. Thus, for my blog I used a vector of booleans; I'm more interested in the concept of bloom filters than the low-level implementation details.<div>
<br></div><div>I don't know if Racket provides bit vectors. My Standard Prelude does provide them, at <a href="http://programmingpraxis.com/contents/standard-prelude/#bits">http://programmingpraxis.com/contents/standard-prelude/#bits</a>.<br>
<br><div class="gmail_quote">On Mon, Jun 6, 2011 at 10:24 AM, Erich Rast <span dir="ltr"><<a href="mailto:erich@snafu.de">erich@snafu.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Thanks a lot, that's a very nice place to start (interesting blog, too).<br>
<br>
I had something similar in mind but was wondering about the<br>
space-efficiency of a vector of booleans. Does the compiler represent<br>
this as a memory area where each boolean corresponds to a single bit?<br>
<br>
That would be cool but my fear is that it doesn't.<br>
<br>
For the record, this is for a function that checks user passphrases<br>
against a *gigantic* dictionary of known ones.<br>
<br>
Best,<br>
<font color="#888888"><br>
Erich<br>
</font><div><div></div><div class="h5"><br>
<br>
On Mon, 2011-06-06 at 09:56 -0500, Phil Bewig wrote:<br>
> I implemented a spell checker using a Bloom filter<br>
> at <a href="http://programmingpraxis.com/2009/04/21/probabilistic-spell-checking/" target="_blank">http://programmingpraxis.com/2009/04/21/probabilistic-spell-checking/</a>.<br>
><br>
> On Mon, Jun 6, 2011 at 9:48 AM, Erich Rast <<a href="mailto:erich@snafu.de">erich@snafu.de</a>> wrote:<br>
> Hi,<br>
><br>
> I need to check whether a given string already occurs in a<br>
> list of<br>
> several million strings, where occasional false positives are<br>
> acceptable.<br>
><br>
> Before reinventing the wheel, has anybody already implemented<br>
> a<br>
> space-efficient Bloom filter in racket and would like to share<br>
> it?<br>
><br>
> Or, what else would you recommend?<br>
><br>
> Best,<br>
><br>
> Erich<br>
><br>
><br>
><br>
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<br>
</div></div></blockquote></div><br></div>