Index on elements of an array

Is it possible to create an index on the elements of an array, or a
functional index on a set-returning function?

The index only needs to speed up queries for specific elements (using
a simple membership test, position in the array does not matter) and
perhaps range queries. The indexed types include integers and text
strings, and possibly more (IP addresses, for instance). The number
of elements per indexed array rarely exceeds 4, I think.

I fear that the distribution of values makes the intarray module and
full text search inappropriate choices (lots of values unique to a
specific row).

--
Florian Weimer <fweimer(at)bfk(dot)de>
BFK edv-consulting GmbH http://www.bfk.de/
Kriegsstraße 100 tel: +49-721-96201-1
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