+and compile_path paths trans states =
+ List.fold_left (fun (aphi, atrans, astates) p ->
+ let phi, ntrans, nstates = compile_single_path p atrans astates in
+ (F.or_ phi aphi),
+ ntrans,
+ nstates) (F.false_,trans,states) paths
+
+and compile_single_path p trans states =
+ let steps =
+ match p with
+ | Absolute steps ->
+ (Ancestor false, (QNameSet.singleton QName.document,
+ Tree.NodeKind.Node), [])
+ :: steps
+ | Relative steps -> steps
+ in
+ compile_step_list steps trans states
+
+and compile_step_list l trans states =
+ match l with
+ | [] -> F.true_, trans, states
+ | (axis, test, elist) :: ll ->
+ let phi0, trans0, states0 = compile_step_list ll trans states in
+ let phi1, trans1, states1 =
+ compile_axis_test axis test phi0 trans0 states0
+ in
+ List.fold_left (fun (aphi, atrans, astates) e ->
+ let ephi, etrans, estates = compile_expr e atrans astates in
+ aphi %% ephi, etrans, estates) (phi1, trans1, states1) elist
+
+(**
+ Compile the top-level XPath query in reverse (doing downward
+ to the last top-level state):
+ /a0::t0[p0]/.../an-1::tn-1[pn-1]/an::tn[pn] becomes:
+ self::node()[ pn and
+ self::tn[pn]/inv(an)::(tn-1)[pn-1]/.../inv(a1)::t0[p0]/inv(a0)::document()]
+
+ /child::a/attribute::b
+ self::@b/parent::a/parent::doc()
+*)
+
+let compile_top_level_step_list l trans states =
+ let rec loop l trans states phi_above =
+ match l with
+ | [] -> assert false
+ | (axis, (test,kind), elist) :: ll ->
+ let phi0, trans0, states0 =
+ compile_axis_test (invert_axis axis)
+ (QNameSet.any, Tree.NodeKind.Node)
+ phi_above trans states
+ in
+ (* Only select attribute nodes if the previous axis
+ is attribute *)
+ let phi0 =
+ if axis != Attribute then
+ phi0 %% (F.not_ F.is_attribute)
+ else phi0
+ in
+ match ll with
+ [] ->
+ let phi1, trans1, states1 =
+ List.fold_left (fun (aphi, atrans, astates) e ->
+ let ephi, etrans, estates = compile_expr e atrans astates in
+ aphi %% ephi, etrans, estates) (phi0, trans0, states0) elist
+ in
+ let _, trans2, states2 =
+ compile_axis_test Self (test,kind) phi1 trans1 states1
+ in
+ let marking_state =
+ StateSet.choose (StateSet.diff states2 states1)
+ in
+ marking_state, trans2, states2
+ | _ ->
+ let phi1, trans1, states1 =
+ compile_axis_test Self (test,kind) phi0 trans0 states0
+ in
+ let phi2, trans2, states2 =
+ List.fold_left (fun (aphi, atrans, astates) e ->
+ let ephi, etrans, estates = compile_expr e atrans astates in
+ aphi %% ephi, etrans, estates) (phi1, trans1, states1) elist
+ in
+ loop ll trans2 states2 phi2
+ in
+ let starting = State.make () in
+ let phi0, trans0, states0 =
+ compile_axis_test
+ Self
+ (QNameSet.any, Tree.NodeKind.Node)
+ (F.stay starting)
+ trans
+ states
+ in
+ let mstates, trans, states = loop l trans0 states0 phi0 in
+ starting, mstates, trans, states
+;;
+
+let path p =
+ let sstates, mstates, trans, states =
+ List.fold_left (fun (ass, ams, atrs, asts) p ->
+ let ss, ms, natrs, nasts =
+ match p with
+ | Absolute l | Relative l -> compile_top_level_step_list l atrs asts
+ in
+ (StateSet.add ss ass),
+ (StateSet.add ms ams),
+ natrs,
+ nasts) (StateSet.empty, StateSet.empty, [], StateSet.empty) p
+ in
+ let builder = Ata.Builder.make () in
+ (** ensure that we have a single selecting state at the end *)
+ let phi_sel = StateSet.fold (fun q acc -> F.or_ (F.stay q) acc) mstates F.false_ in
+ let q_sel = State.make () in
+ let states = StateSet.add q_sel states in
+ let mstates = StateSet.singleton q_sel in
+ let trans = (q_sel, [QNameSet.any, phi_sel]) :: trans in
+ StateSet.iter
+ (Ata.Builder.add_state builder ~starting:true) sstates;
+ StateSet.iter
+ (Ata.Builder.add_state builder ~selecting:true) mstates;
+ StateSet.iter
+ (Ata.Builder.add_state builder) states;
+ List.iter (fun (q, l) ->
+ List.iter (fun (lab, phi) ->
+ Ata.Builder.add_trans builder q lab phi
+ ) l) trans;
+ Ata.Builder.finalize builder