Thanks for these pointers, Ken. And belated thanks to Oleg for his reply in June. Impressive tricks!<br><br>Perhaps I'm not the only person who'd prefer a more straightforward formulation of backtracking search? Cheers,
<br><br> - Conal<br><br><div><span class="gmail_quote">On 7/31/07, <b class="gmail_sendername">Chung-chieh Shan</b> <<a href="mailto:ccshan@post.harvard.edu">ccshan@post.harvard.edu</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Conal Elliott <<a href="mailto:conal@conal.net">conal@conal.net</a>> wrote in article <<a href="mailto:ea8ae9fb0707311208j9f3fcf7m92bef8f54aea3dd8@mail.gmail.com">ea8ae9fb0707311208j9f3fcf7m92bef8f54aea3dd8@mail.gmail.com
</a>> in gmane.comp.lang.haskell.general:<br>> I keep running into situations in which I want more powerful search in<br>> selecting type class instances.<br><br>I agree that it's quite useful for instance search to backtrack, if not
<br>desirable in all cases. Proof search is program search, after all.<br><br>Of course, allowing undecidable instances, we can build backtracking<br>into instance search ourselves by representing the state of a<br>backtracking machine as a type.
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</a><br>And if thou gaze into the abyss, the abyss...actually finds you pretty creepy.<br><br>_______________________________________________<br>Haskell mailing list<br><a href="mailto:Haskell@haskell.org">Haskell@haskell.org
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