Add support for BC years

[jkeck]

We have a few collections that have negative year values (Papyrus Manuscripts) that don't show up properly in the date slider. We currently remove negative years from the facet that drives the date facet, however we get reports from confused users from time to time.

I am creating this ticket as a place to discuss the feasibility of adding this support to blacklight_range_limit.

[jrochkind]

Should be possible, assuming you can figure out how to make Solr deal with it.

I guess they'd be indexed in Solr as actual negative years, like you say, since the func is currently based on a Solr numeric (not date) field (and thus theoretically avail for non-date numeric data too).

Would you want to display them as "BC", or as actual negative years too? It should probably be possible to display them as "BC" on the flot chart, using flot custom formatting options. Not sure about the slider.

As a first pass, if you actually want to display them as negative numbers -- I'm not sure what would keep it from just working, actually. Try indexing negative numbers into your Solr field, I wonder if it'll just plain work. If not, I suspect there will only be minor tweaks needed to make it work.

[cbeer]

(See also #17)

[atz]

See also #34 for date support overall.

[starsplatter]

I've just hit the BC date problem for a couple of collections. Has anyone got any work in progress on this?