Binary_searchable.Which_target_by_key
type t = [
| `Last_strictly_less_than
| < elt X |
| `Last_less_than_or_equal_to
| <= elt X |
| `Last_equal_to
| = elt X |
| `First_equal_to
| X = elt |
| `First_greater_than_or_equal_to
| X >= elt |
| `First_strictly_greater_than
| X > elt |
]
val all : t list