Versions (u.43152da62fb527f3e9d3bf8e7a20fd05.reason.3.16.0.doc.reason.ocaml-migrate-parsetree.Reason

Abstracting an OCaml frontend

module type Ast = sig ... end

Abstract view of a version of an OCaml Ast

type 'a _types = 'a
  constraint
    'a =
    < out_value : _
    ; out_type : _
    ; out_class_type : _
    ; out_module_type : _
    ; out_sig_item : _
    ; out_type_extension : _
    ; out_phrase : _ >

type 'a get_out_value = 'x constraint 'a _types = < out_value : 'x.. >

type 'a get_out_type = 'x constraint 'a _types = < out_type : 'x.. >

type 'a get_out_class_type = 'x constraint 'a _types = < out_class_type : 'x.. >

type 'a get_out_module_type = 'x constraint 'a _types = < out_module_type : 'x.. >

type 'a get_out_sig_item = 'x constraint 'a _types = < out_sig_item : 'x.. >

type 'a get_out_type_extension = 'x constraint 'a _types = < out_type_extension : 'x.. >

type 'a get_out_phrase = 'x constraint 'a _types = < out_phrase : 'x.. >

type _ witnesses = private ..

A version of the OCaml frontend packs the ast with type witnesses so that equalities can be recovered dynamically.

type _ migration_info

migration_info is an opaque type that is used to generate migration functions.

module type OCaml_version = sig ... end

An OCaml frontend versions an Ast, version number and some witnesses for conversion.

type 'types ocaml_version =
  (module OCaml_version
  with type Ast.Outcometree.out_class_type = 'types get_out_class_type
   and type Ast.Outcometree.out_module_type = 'types get_out_module_type
   and type Ast.Outcometree.out_phrase = 'types get_out_phrase
   and type Ast.Outcometree.out_sig_item = 'types get_out_sig_item
   and type Ast.Outcometree.out_type = 'types get_out_type
   and type Ast.Outcometree.out_type_extension = 'types get_out_type_extension
   and type Ast.Outcometree.out_value = 'types get_out_value)

Representing an ocaml version in type language

Concrete frontend instances

module OCaml_402 : OCaml_version with module Ast = Ast_402

val ocaml_402 : OCaml_402.types ocaml_version

module OCaml_403 : OCaml_version with module Ast = Ast_403

val ocaml_403 : OCaml_403.types ocaml_version

module OCaml_404 : OCaml_version with module Ast = Ast_404

val ocaml_404 : OCaml_404.types ocaml_version

module OCaml_405 : OCaml_version with module Ast = Ast_405

val ocaml_405 : OCaml_405.types ocaml_version

module OCaml_406 : OCaml_version with module Ast = Ast_406

val ocaml_406 : OCaml_406.types ocaml_version

module OCaml_407 : OCaml_version with module Ast = Ast_407

val ocaml_407 : OCaml_407.types ocaml_version

module OCaml_408 : OCaml_version with module Ast = Ast_408

val ocaml_408 : OCaml_408.types ocaml_version

module OCaml_409 : OCaml_version with module Ast = Ast_409

val ocaml_409 : OCaml_409.types ocaml_version

module OCaml_410 : OCaml_version with module Ast = Ast_410

val ocaml_410 : OCaml_410.types ocaml_version

module OCaml_411 : OCaml_version with module Ast = Ast_411

val ocaml_411 : OCaml_411.types ocaml_version

module OCaml_412 : OCaml_version with module Ast = Ast_412

val ocaml_412 : OCaml_412.types ocaml_version

module OCaml_413 : OCaml_version with module Ast = Ast_413

val ocaml_413 : OCaml_413.types ocaml_version

module OCaml_414 : OCaml_version with module Ast = Ast_414

val ocaml_414 : OCaml_414.types ocaml_version

module OCaml_500 : OCaml_version with module Ast = Ast_500

val ocaml_500 : OCaml_500.types ocaml_version

module OCaml_51 : OCaml_version with module Ast = Ast_51

val ocaml_51 : OCaml_51.types ocaml_version

module OCaml_52 : OCaml_version with module Ast = Ast_52

val ocaml_52 : OCaml_52.types ocaml_version

module OCaml_53 : OCaml_version with module Ast = Reason_omp__.Ast_53

val ocaml_53 : OCaml_53.types ocaml_version

module OCaml_current = OCaml_410

val ocaml_current : OCaml_current.types ocaml_version

val all_versions : (module OCaml_version) list

Migrating between different versions

type ('a, 'b) type_comparison =

| Lt : ('a, 'b) type_comparison
| Eq : ('a, 'a) type_comparison
| Gt : ('a, 'b) type_comparison

val compare_ocaml_version : 
  'a ocaml_version ->
  'b ocaml_version ->
  ('a, 'b) type_comparison

type ('from, 'to_) migration_functions = {

copy_out_value : 'from get_out_value -> 'to_ get_out_value;
copy_out_type : 'from get_out_type -> 'to_ get_out_type;
copy_out_class_type : 'from get_out_class_type -> 'to_ get_out_class_type;
copy_out_module_type : 'from get_out_module_type -> 'to_ get_out_module_type;
copy_out_sig_item : 'from get_out_sig_item -> 'to_ get_out_sig_item;
copy_out_type_extension : 'from get_out_type_extension -> 'to_ get_out_type_extension;
copy_out_phrase : 'from get_out_phrase -> 'to_ get_out_phrase;

}

A record for migrating each AST construct between two known versions

val migration_identity : ('a, 'a) migration_functions

Migrating to the same version is no-op

val migration_compose : 
  ('a, 'b) migration_functions ->
  ('b, 'c) migration_functions ->
  ('a, 'c) migration_functions

Migrations can be composed

Represent the next or previous version of an Ast

type 'from immediate_migration =

| No_migration : 'from immediate_migration
(*
Cannot migrate earliest or latest supported version
*)
| Immediate_migration : ('from, 'to_) migration_functions * 'to_ ocaml_version -> 'from immediate_migration
(*
Pack the migration functions and the new version
*)

val immediate_migration : 
  'types ocaml_version ->
  [< `Next | `Previous ] ->
  'types immediate_migration

val migrate : 
  'from ocaml_version ->
  'to_ ocaml_version ->
  ('from, 'to_) migration_functions

Convenience definitions

module Convert (A : OCaml_version) (B : OCaml_version) : sig ... end

Module level migration