(** Monomorphization of type definitions *)

type original_types = (string, string * int) Hashtbl.t
(** To support the generation of annotations for types that are created
    during the monomorphization process, a mapping must be kept connecting
    the monomorphic type name to the original polymorphic one, including its
    original number of parameters.

    This table is only used in producing those annotations to support the
    Atdgen command line option -o-name-overlap. It can probably be ignored
    for most uses of expand_module_body.
*)

val expand_module_body :
  ?prefix:string ->
  ?keep_builtins:bool ->
  ?keep_poly:bool ->
  ?debug:bool ->
  Ast.module_body -> Ast.module_body * original_types
(**
   Monomorphization of type expressions.

   @param prefix prefix to use for new type names. Default is ["_"].

   @param keep_builtins preserve occurrences of the built-in parametrized
   types such as [list] or [option].
   Default is [false].

   @param keep_poly return definitions for the parametrized types.
   Default is [false].

   @param debug keep meaningful but non ATD-compliant names for new type names.
   Default is [false].

   The goal is to inline each parametrized type definition as much as possible,
   allowing code generators to create more efficient code directly:

{v
  type ('a, 'b) t = [ Foo of 'a | Bar of 'b ]
  type int_t = (int, int) t
v}

  becomes:

{v
  type int_t = _1
  type _1 = [ Foo of int | Bar of int ]
v}

  A secondary goal is to factor out type subexpressions in order for
  the code generators to produce less code:

{v
  type x = \{ x : int list }
  type y = \{ y : int list option }
v}

  becomes:

{v
  type x = \{ x : _1 }
  type y = \{ y : _2 }
  type _1 = int list   (* `int list' now occurs only once *)
  type _2 = _1 option
v}

  By default, only parameterless type definitions are returned.
  The [keep_poly] option allows to return parametrized type definitions as
  well.

  Input:

{v
  type 'a abs = abstract
  type int_abs = int abs
  type 'a tree = [ Leaf of 'a | Node of ('a tree * 'a tree) ]
  type t = int tree
  type x = [ Foo | Bar ] tree
v}

  Output (pseudo-syntax where quoted strings indicate unique type identifiers):

{v
  type "int abs" = int abs
  type int_abs = "int abs"

  type 'a tree = [ Leaf of 'a | Node of ('a tree * 'a tree) ]
    (* only if keep_poly = true *)

  type "int tree" = [ Leaf of int | Node of ("int tree" * "int tree") ]
  type t = "int tree"
  type "[ Foo | Bar ] tree" =
    [ Leaf of [ Foo | Bar ]
    | Node of ("[ Foo | Bar ] tree" * "[ Foo | Bar ] tree") ]
  type x = "[ Foo | Bar ] tree"
v}

*)
