Datarepr (ocaml.Datarepr)

val extension_descr : 
  current_unit:Unit_info.t option ->
  Path.t ->
  Types.extension_constructor ->
  Types.constructor_description

val labels_of_type : 
  Path.t ->
  Types.type_declaration ->
  (Ident.t * Types.label_description) list

val constructors_of_type : 
  current_unit:Unit_info.t option ->
  Path.t ->
  Types.type_declaration ->
  (Ident.t * Types.constructor_description) list

exception Constr_not_found

val find_constr_by_tag : 
  Types.constructor_tag ->
  Types.constructor_declaration list ->
  Types.constructor_declaration

val constructor_existentials : 
  Types.constructor_arguments ->
  Types.type_expr option ->
  Types.type_expr list * Types.type_expr list

Takes cd_args and cd_res from a constructor_declaration and returns:

the types of the constructor's arguments
the existential variables introduced by the constructor