Splitting kernel universe code in two modules.

1. The Univ module now only cares about definitions about universes.
2. The UGraph module contains the algorithm responsible for aciclicity.

1 files changed, 63 insertions, 0 deletions

diff --git a/kernel/uGraph.mli b/kernel/uGraph.mli
new file mode 100644
index 000000000..e95cf4d1c
--- /dev/null
+++ b/kernel/uGraph.mli
@@ -0,0 +1,63 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2015     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+open Univ
+
+(** {6 Graphs of universes. } *)
+
+type t
+
+type universes = t
+
+type 'a check_function = universes -> 'a -> 'a -> bool
+val check_leq : universe check_function
+val check_eq : universe check_function
+
+(** The empty graph of universes *)
+val empty_universes : universes
+
+(** The initial graph of universes: Prop < Set *)
+val initial_universes : universes
+
+val is_initial_universes : universes -> bool
+
+val sort_universes : universes -> universes
+
+(** Adds a universe to the graph, ensuring it is >= or > Set.
+   @raises AlreadyDeclared if the level is already declared in the graph. *)
+
+exception AlreadyDeclared
+
+val add_universe : universe_level -> bool -> universes -> universes
+
+(** {6 ... } *)
+(** Merge of constraints in a universes graph.
+  The function [merge_constraints] merges a set of constraints in a given
+  universes graph. It raises the exception [UniverseInconsistency] if the
+  constraints are not satisfiable. *)
+
+val enforce_constraint : univ_constraint -> universes -> universes
+val merge_constraints : constraints -> universes -> universes
+
+val constraints_of_universes : universes -> constraints
+
+val check_constraint  : universes -> univ_constraint -> bool
+val check_constraints : constraints -> universes -> bool
+
+val check_eq_instances : Instance.t check_function
+(** Check equality of instances w.r.t. a universe graph *)
+
+(** {6 Pretty-printing of universes. } *)
+
+val pr_universes : (Level.t -> Pp.std_ppcmds) -> universes -> Pp.std_ppcmds
+
+(** {6 Dumping to a file } *)
+
+val dump_universes :
+  (constraint_type -> string -> string -> unit) ->
+  universes -> unit