[Haskell-cafe] Purely Functional Data Structures
wagner.andrew at gmail.com
Sun Mar 8 22:11:12 EDT 2009
So...is there some reason this is in the hApps package?
On Sat, Mar 7, 2009 at 9:04 PM, Jeremy Shaw <jeremy at n-heptane.com> wrote:
> At Sun, 08 Mar 2009 00:13:14 +0100,
> G?uenther Schmidt wrote:
> > In SQL I would have the data indexed by several
> > different columns, if I use maps I'd only have one key, so if I need to
> > lookup data in the map by a value that is not the key the lookups will
> > become quite expensive.
> happstack-ixset offers a data-type similar to Map except that you can
> have multiple keys. You can even have keys that are calculated from
> the data but don't actually appear in the data itself. For, example,
> if your ixset just contains Strings, one of the keys could be the
> length of the String.
> happstack-ixset (and its dependencies) also offers compact
> serialization/deserialization of the ixset to disk, data migration
> options, and a smattering of other features that may or may not be
> useful to you.
> While happstack-ixset is built to work with happstack, it is does not
> depend on the happstack http server or persistent store layer, so it
> should be useful even if you are not being an application server.
> - jeremy
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
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