[elephant-devel] remove-current-kv does not work as advertised!

[Alex Mizrahi]

(defvar *current-cursor* nil
  "This dynamic variable is referenced only when deleting elements
   using the following function.  This allows mapping functions to
   delete elements as they map.  This is safe as we don't revisit
   values during maps")

(defun remove-current-kv ()
  (unless *current-cursor*
    (error "Cannot call remove-current-kv outside of a map-btree or 
map-index function argument"))
  (cursor-delete *current-cursor*))

it's supposed that while cursor is iterated in map-btree, we can remove 
current element and then jump to next.

but cursor-delete leaves cursor unitialized, so cursor-next will instead 
jump to first item, and iteration will be restarted.

so, finally it will work (i think), but it's damn slow and painful 
procedure.

i think it's better to remove this functionality, or fix this. if we are not 
going to change cursor-delete
semantics, a way to delete item without making cursor unintialized is 
something like:

(defun remove-current-kv ()
  (unless *current-cursor* (error "Cannot call remove-current-kv outside of 
a map-btree or map-index function argument"))
  (let ((c (cursor-duplicate *current-cursor*)))
     (cursor-delete c)))

but i dunno if it will work in BDB