This is an insanely ugly method.
This is an insanely ugly method. But, it works for our use-case. We need to retrieve values for Locs that are in the breadcrumb nav for a particular Loc. To do so, we have to extract values for those Locs that have PathParams *from* the current Loc's value (since it's the only value that's available). Extracting single values is easily done with pattern-matching. Extracting the multi-param values is more difficult.
Returns the value(s) needed to construct links/titles for Locs that are in the current Loc's path (breadcrumbs).