user-supplied hash-functions

This page is part of the web mail archives of SRFI 113 from before July 7th, 2015. The new archives for SRFI 113 contain all messages, not just those from before July 7th, 2015.

To: srfi-113@xxxxxxxxxxxxxxxxx

Subject: user-supplied hash-functions

From: Jim Rees <jimreesma@xxxxxxxxx>

Date: Mon, 10 Jun 2013 12:18:09 -0400

Delivered-to: srfi-113@xxxxxxxxxxxxxxxxx

Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type; bh=VrpBzV3TeFqJV3ZOcg1G2WqY30xiWR2F78v2nqLPW40=; b=jpglZVWdHpRRowRxAba/SkdrAZHi20i2MjwH/pWGDJcXpZ7Q0oWV+ZX/dJZuH5H0Nh ukjfA5nHBpHQUsymu8NRVBDRGz1U/K5xzhIyj5iWIxIrYNkPC79OOallPSxn81AWxE7G 2V7DmhEbORIs5Ub8ub1KnTGH6guLxEE7bTGcU5+P/ZXdlWE77Z+ryuz6itumpgAATZ+Q AHc6IWRaCDurkoDe6TRf3ShrY8DeZzeY0gbX8kpiZT983+ct2u8Pf0hjSY/JV6My8CXM M0nDZMSx42yCSpXAEYu9ilWzm7AEUCKSADryXJStfbk28bHnhp1zvPxSMUGRYub/6LG0 IkUw==

In combination with the Issues section of HashTablesCowan, why the apparent bias against user-supplied hash-functions?

While sets keyed by simple types (numbers, symbols, strings, characters, ...) certainly are extremely useful, I also use complex structures with mutable elements not contributing to the equivalence predicate (or hashfunction), and I'd certainly want also to use them with records (distinguished by contents) too. Â Â

SRFI-113 can't do either of these as far as I can tell, but I can live with that if a separate hashtable api gives me the added generality.