module Identifiable: Identifiable
module type S =sig
..end
module Make:functor (
M
:
sig
type
t
include Stringable.S
val hash :t -> int
val module_name :string
val t_of_sexp :Sexplib.Sexp.t -> t
val sexp_of_t :t -> Sexplib.Sexp.t
val compare :t -> t -> int
val bin_t :t Bin_prot.Type_class.t
val bin_read_t :t Bin_prot.Read_ml.reader
val bin_read_t_ :t Bin_prot.Unsafe_read_c.reader
val bin_read_t__ :(int -> t) Bin_prot.Unsafe_read_c.reader
val bin_reader_t :t Bin_prot.Type_class.reader
val bin_size_t :t Bin_prot.Size.sizer
val bin_write_t :t Bin_prot.Write_ml.writer
val bin_write_t_ :t Bin_prot.Unsafe_write_c.writer
val bin_writer_t :t Bin_prot.Type_class.writer
end
) ->
S
with type t := M.t
Identifiable.Of_sexpable
, but we removed it because it
encouraged a terrible implementation of Identifiable.S
. In particular, hash
,
compare
, and bin_io
were all built by converting the type to a sexp, and then to a
string.
One should use Identifiable.Make
instead. Here is what a use might look like:
module Id = struct
module T = struct
type t = A | B with bin_io, compare, sexp
let hash (t : t) = Hashtbl.hash t
include Sexpable.To_stringable (struct type nonrec t = t with sexp end)
end
include T
include Identifiable.Make (T)
end
We also removed Identifiable.Of_stringable
, which wasn't as obviously bad as
Of_sexpable
. But it still used the string as an intermediate, which is often the
wrong choice -- especially for compare
and bin_io
, that can be generated by
preprocessors.