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(************************************************************************)
(* * The Coq Proof Assistant / The Coq Development Team *)
(* v * INRIA, CNRS and contributors - Copyright 1999-2018 *)
(* <O___,, * (see CREDITS file for the list of authors) *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(* * (see LICENSE file for the text of the license) *)
(************************************************************************)
(** {6 Search strategies. } *)
(** {6 ... } *)
(** A search problem implements the following signature [SearchProblem].
[state] is the type of states of the search tree.
[branching] is the branching function; if [branching s] returns an
empty list, then search from [s] is aborted; successors of [s] are
recursively searched in the order they appear in the list.
[success] determines whether a given state is a success.
[pp] is a pretty-printer for states used in debugging versions of the
search functions. *)
module type SearchProblem = sig
type state
val branching : state -> state list
val success : state -> bool
val pp : state -> Pp.t
end
(** {6 ... } *)
(** Functor [Make] returns some search functions given a search problem.
Search functions raise [Not_found] if no success is found.
States are always visited in the order they appear in the
output of [branching] (whatever the search method is).
Debugging versions of the search functions print the position of the
visited state together with the state it-self (using [S.pp]). *)
module Make : functor(S : SearchProblem) -> sig
val depth_first : S.state -> S.state
val debug_depth_first : S.state -> S.state
val breadth_first : S.state -> S.state
val debug_breadth_first : S.state -> S.state
end
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