package ppx_deriving

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Type-driven code generation for OCaml






5.2.1 (02/02/2021)

  • Allow Ast_convenience's functions to be given a full path ident (e.g. M.ident) #248 (Kate Deplaix)

  • Add a deprecation notice of the API in the README. The next step of the deprecation is going to be in the form of a [@@@ocaml.deprecated ...] alert on the API module and the reimplementation of the individual plugins using the ppxlib API. (Kate Deplaix and Gabriel Scherer)

5.2 (25/11/2020)

  • Update to ppxlib 0.20.0 #237 #239 #243 #245 (Kate Deplaix, Jérémie Dimino, Thierry Martinez, Gabriel Scherer)

  • Upgrade testsuite from ounit to ounit2 #241 (Kate Deplaix)

  • (almost) use the set of standard flags from dune #246 (Kate Deplaix)

5.1 (26/10/2020)

  • Update to ppxlib 0.15.0 #235 (Kate Deplaix)

5.0 (26/10/2020)

  • Migrate to ppxlib #206, #210 (Anton Kochkov, Gabriel Scherer, Thierry Martinez)


  • Add support for OCaml 4.11.

    • Ppx_deriving.string_of_{constant,expression}_opt to destruct Pconst_string in a version-independent way #220, #222 (Kate Deplaix, Thierry Martinez, review by Gabriel Scherer)

  • Stronger type equalities in Ppx_deriving_runtime (for instance, Ppx_deriving_runtime.result and Result.result are now compatible with all OCaml versions) #223, #225 (Thierry Martinez, review by Gabriel Scherer)

  • Ppx_deriving_runtime.Option compatibility module #222 (Thierry Martinez, review by Gabriel Scherer)


  • Add support for OCaml 4.10 #211 (Kate Deplaix, review by Gabriel Scherer)


  • Restore support for OCaml 4.02.3 #188 (ELLIOTTCABLE)

  • workaround Location.input_filename being empty when using reason-language-server #196 (Ryan Artecona)

  • Add support for OCaml 4.08.0 #193, #197, #200 (Gabriel Scherer)


  • use Format through Ppx_deriving_runtime to avoid deprecation warning for users of JaneStreet Base (Stephen Bastians and Gabriel Scherer, review by whitequark)

  • silence a ambiguous-field warning (41) in generated code #163 (Étienne Millon, review by Gabriel Scherer)

  • use dune #170 (Rudi Grinberg, Jérémie Dimino)

  • silence an unused-value warning for show #179 (Nathan Rebours)


  • Add support for OCaml 4.06.0 #154, #155, #156, #159 (Gabriel Scherer, Fabian, Leonid Rozenberg)

  • Consider { with_path = false } when printing record fields #157 (François Pottier)


  • Add support for OCaml 4.05.0.

  • Use the ocaml-migrate-parsetree library to support multiple versions of OCaml.

  • Fix comparison order of fields in records (#136).

  • Silence an unused rec flag warning in generated code (#137).

  • Monomorphize comparison function for builtin types (#115)

  • Raise an error when type nonrec is encountered (#116).

  • Display an error message when dynamic package loading fails.

  • Add a with_path option to @@deriving to skip the module path in generated code (#120).

The homepage for the project has now moved to:


  • Fix type error with inheritied polymorphic variant type in [@@deriving map].

  • Fix incorrect handling of multi-argument constructors in [@@deriving show].

  • Add API hooks for ppx_type_conv.


  • Show, eq, ord, map, iter, fold: add support for Result.result.

  • Ppx_deriving.Arg: use Result.result instead of polymorphic variants.

  • Ppx_deriving.sanitize: parameterize over an opened module.

  • Add support for [@@deriving] in module type declarations.

  • Add support for loading findlib packages instead of just files in ppx_deriving_main.

  • Treat types explicitly qualified with Pervasives also as builtin.

  • Compatibility with statically linked ppx drivers.


  • Show, eq, ord: hygienically invoke functions from referenced modules (such as X.pp for X.t when deriving show) to coexist with modules shadowing ones from standard library.

  • Iter, map, fold: hygienically invoke List and Array functions.


  • Implement hygiene: Ppx_deriving.{create_quoter,quote,sanitize,with_quoter}.

  • Show, eq, ord: add support for lazy_t.

  • Add support for [@nobuiltin] attribute.

  • Add Ppx_deriving.hash_variant.

  • Remove allow_std_type_shadowing option.

  • Remove Ppx_deriving.extract_typename_of_type_group.


  • Fix breakage occurring with 4.02.2 w.r.t record labels

  • Fix prefixed attribute names ([] and [@foo.attr]).

  • Add allow_std_type_shadowing option for eq and show.


  • Add support for open types.


  • New plugin: create.

  • Show, eq, ord: handle _.

  • Show, eq, ord, map, iter, fold: handle inheriting from a parametric polymorphic variant type.

  • Make Ppx_deriving.poly_{fun,arrow}_of_type_decl construct functions in correct order. This also fixes all derivers with types with more than one parameter.

  • Add Ppx_deriving.fold_{left,right}_type_decl.


  • Make deriver names lowercase.

  • Remove Findlib+dynlink integration. All derivers must now be explicitly required.

  • Allow shortening [%derive.x:] to [%x:] when deriver x exists.

  • Make Ppx_deriving.core_type field optional to allow ignoring unsupported [%x:] shorthands.

  • Add support for [@@deriving foo { optional = true }] that does not error out if foo is missing, useful for optional dependencies.

  • Rename ~name and ~prefix of Ppx_deriving.attr and Ppx_deriving.Arg.payload to ~deriver.

  • Renamed Ppx_deriving.Arg.payload to get_attr.

  • Add Ppx_deriving.Arg.get_expr and get_flag.


  • Show, Eq, Ord, Iter, Fold: handle ref.

  • Show: handle functions.

  • Show: include break hints in format strings.

  • Show: pull fprintf into local environment.

  • Show: add [@polyprinter] and [@opaque].

  • Add Ppx_deriving.Arg.expr.


  • New plugins: Enum, Iter, Map, Fold.

  • All plugins: don't concatenate affix if type is named t.

  • Add [%derive.Foo:] shorthand.

  • Show, Eq, Ord: add support for list, array, option.

  • Show: include full module path in output, including for types with manifest.

  • A lot of changes in Ppx_deriving interface.


  • Initial release.