Passing multi-select choices to :preview-fn

[sheluchin]

Thanks for this handy library. I'm just wondering if you might have some idea of how we could modify the code to allow all of the selected choices to be passed to the preview-fn. At the moment, it only passes the current item.

In fzf, there is the {+} placeholder which is produced a space-separated list of the selected lines (see junegunn/fzf#3574 (reply in thread)). I attempted to get this working locally but couldn't quite figure out how to handle it with the embedded preview server/bbnc namespace.

You can achieve a similar effect using something like:

  (fzf {:preview "echo {+} | bb -e  '(->> (str/split (slurp *in*) #\" \") (map (comp parse-long str/trim)) (apply +))'"
        :multi true}
       [1 2 3]))

but it would be a bit nicer if we could receive the selections as a vector in preview-fn.