(** The context given to rewriting rules when expanding. *)

module Base : sig
  type t
  (** Type for the location independent parts of the expansion context *)

  val code_path : t -> Code_path.t
  (** Return the code path for the given context In Driver, Deriving and
      Extension, the context is initialized so that the [file_path] component of
      the [code_path] is determined from the first location found in the input
      AST. That means that:

      - It's the empty string in empty structures or signatures
      - It can be altered by line directives *)

  val input_name : t -> string
  (** Return the input name for the given context. In Driver, Deriving and
      Extension, the context argument is initialized so that the [input_name]
      matches the input filename passed to the driver on the command line. That
      means that:

      - It has a value even for empty files
      - It is not affected by line directives
      - It is ["_none_"] when using [Driver.map_structure] or
        [Driver.map_signature] *)

  val tool_name : t -> string
  (** Can be used within a ppx preprocessor to know which tool is calling it
      ["ocamlc"], ["ocamlopt"], ["ocamldep"], ["ocaml"], ... . *)

  (**/**)

  (** Undocumented section *)

  val top_level : tool_name:string -> file_path:string -> input_name:string -> t
  (** Build a new base context at the top level of the given file with the given
      calling tool name. *)

  val enter_expr : t -> t
  (** Proxy functions to update the wrapped code path. See code_path.mli for
      details. *)

  val enter_module : loc:Location.t -> string -> t -> t
  val enter_value : loc:Location.t -> string -> t -> t
end

module Extension : sig
  type t
  (** Type of expansion contexts for extensions *)

  val extension_point_loc : t -> Location.t
  (** Return the location of the extension point being expanded *)

  val code_path : t -> Code_path.t
  (** Return the code path for the given context In Driver, Deriving and
      Extension, the context is initialized so that the [file_path] component of
      the [code_path] is determined from the first location found in the input
      AST. That means that:

      - It's the empty string in empty structures or signatures
      - It can be altered by line directives *)

  val input_name : t -> string
  (** Return the input name for the given context. In Driver, Deriving and
      Extension, the context argument is initialized so that the [input_name]
      matches the input filename passed to the driver on the command line. That
      means that:

      - It has a value even for empty files
      - It is not affected by line directives
      - It is ["_none_"] when using [Driver.map_structure] or
        [Driver.map_signature] *)

  val tool_name : t -> string
  (** Can be used within a ppx preprocessor to know which tool is calling it
      ["ocamlc"], ["ocamlopt"], ["ocamldep"], ["ocaml"], ... . *)

  val with_loc_and_path : (loc:Location.t -> path:string -> 'a) -> ctxt:t -> 'a
  (** Wrap a [fun ~loc ~path] into a [fun ~ctxt] *)

  (**/**)

  (** Undocumented section *)

  val make : extension_point_loc:Location.t -> base:Base.t -> unit -> t
  (** Build a new expansion context with the given extension point location and
      base context *)
end

module Deriver : sig
  type t
  (** Type of expansion contexts for derivers *)

  val derived_item_loc : t -> Location.t
  (** Return the location of the item to which the deriver is being applied *)

  val code_path : t -> Code_path.t
  (** Return the code path for the given context In Driver, Deriving and
      Extension, the context is initialized so that the [file_path] component of
      the [code_path] is determined from the first location found in the input
      AST. That means that:

      - It's the empty string in empty structures or signatures
      - It can be altered by line directives *)

  val input_name : t -> string
  (** Return the input name for the given context. In Driver, Deriving and
      Extension, the context argument is initialized so that the [input_name]
      matches the input filename passed to the driver on the command line. That
      means that:

      - It has a value even for empty files
      - It is not affected by line directives
      - It is ["_none_"] when using [Driver.map_structure] or
        [Driver.map_signature] *)

  val tool_name : t -> string
  (** Can be used within a ppx preprocessor to know which tool is calling it
      ["ocamlc"], ["ocamlopt"], ["ocamldep"], ["ocaml"], ... . *)

  val with_loc_and_path : (loc:Location.t -> path:string -> 'a) -> ctxt:t -> 'a
  (** Wrap a [fun ~loc ~path] into a [fun ~ctxt] *)

  val inline : t -> bool
  (** Whether the derived code is going to be inlined in the source *)

  (**/**)

  (** Undocumented section *)

  val make :
    derived_item_loc:Location.t -> inline:bool -> base:Base.t -> unit -> t
  (** Build a new expansion context with the given item location and code path *)
end
