module Label: sig end
The set of row labels is defined by the module Label.
type t
The type of row labels.
val compare : t -> t -> int
A function compare definining a total order on row labels must
be provided. This order is used for governing label mutations.
val hash : t -> int
hash lbl returns a hash integer of the label lbl. If
compare lbl1 lbl2 returns 0 then hash lbl1 and hash lbl2
must return the same integer.
val fprint : Format.formatter -> t -> unit
fprint ppf lbl pretty-prints the row label lbl on the
formatter ppf.