Module Migrate_parsetree_versions

Abstracting an OCaml frontend

module type Ast : sig ... end

Abstract view of a version of an OCaml Ast

type 'a _types = 'a constraint 'a = < structure : _; signature : _; toplevel_phrase : _; core_type : _; expression : _; pattern : _; case : _; type_declaration : _; type_extension : _; extension_constructor : _; out_value : _; out_type : _; out_class_type : _; out_module_type : _; out_sig_item : _; out_type_extension : _; out_phrase : _; mapper : _; >
type 'a get_structure = 'x constraint 'a _types = < structure : 'x; .. >
type 'a get_signature = 'x constraint 'a _types = < signature : 'x; .. >
type 'a get_toplevel_phrase = 'x constraint 'a _types = < toplevel_phrase : 'x; .. >
type 'a get_core_type = 'x constraint 'a _types = < core_type : 'x; .. >
type 'a get_expression = 'x constraint 'a _types = < expression : 'x; .. >
type 'a get_pattern = 'x constraint 'a _types = < pattern : 'x; .. >
type 'a get_case = 'x constraint 'a _types = < case : 'x; .. >
type 'a get_type_declaration = 'x constraint 'a _types = < type_declaration : 'x; .. >
type 'a get_type_extension = 'x constraint 'a _types = < type_extension : 'x; .. >
type 'a get_extension_constructor = 'x constraint 'a _types = < extension_constructor : 'x; .. >
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 'a get_mapper = 'x constraint 'a _types = < mapper : 'x; .. >
type _ witnesses

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.Ast_mapper.mapper = 'types get_mapper and 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 and type Ast.Parsetree.case = 'types get_case and type Ast.Parsetree.core_type = 'types get_core_type and type Ast.Parsetree.expression = 'types get_expression and type Ast.Parsetree.extension_constructor = 'types get_extension_constructor and type Ast.Parsetree.pattern = 'types get_pattern and type Ast.Parsetree.signature = 'types get_signature and type Ast.Parsetree.structure = 'types get_structure and type Ast.Parsetree.toplevel_phrase = 'types get_toplevel_phrase and type Ast.Parsetree.type_declaration = 'types get_type_declaration and type Ast.Parsetree.type_extension = 'types get_type_extension)

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_current = OCaml_404
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'btype_comparison
| Eq : ('a'atype_comparison
| Gt : ('a'btype_comparison
val compare_ocaml_version : 'a ocaml_version ‑> 'b ocaml_version ‑> ('a'btype_comparison
type ('from, 'to_) migration_functions = {
copy_structure : 'from get_structure ‑> 'to_ get_structure;
copy_signature : 'from get_signature ‑> 'to_ get_signature;
copy_toplevel_phrase : 'from get_toplevel_phrase ‑> 'to_ get_toplevel_phrase;
copy_core_type : 'from get_core_type ‑> 'to_ get_core_type;
copy_expression : 'from get_expression ‑> 'to_ get_expression;
copy_pattern : 'from get_pattern ‑> 'to_ get_pattern;
copy_case : 'from get_case ‑> 'to_ get_case;
copy_type_declaration : 'from get_type_declaration ‑> 'to_ get_type_declaration;
copy_type_extension : 'from get_type_extension ‑> 'to_ get_type_extension;
copy_extension_constructor : 'from get_extension_constructor ‑> 'to_ get_extension_constructor;
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;
copy_mapper : 'from get_mapper ‑> 'to_ get_mapper;
}

A record for migrating each AST construct between two known versions

val migration_identity : ('a'amigration_functions

Migrating to the same version is no-op

val migration_compose : ('a'bmigration_functions ‑> ('b'cmigration_functions ‑> ('a'cmigration_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 : functor (A : OCaml_version) -> functor (B : OCaml_version) -> sig ... end

Module level migration