open XPath.Ast
open Formula.Infix
-exception Not_core_XPath of path
+exception Not_core_XPath
(** Raised whenever the XPath query contains not implemented structures *)
+let pr_er = Format.err_formatter
+
let trans query =
let asta = Asta.empty in
+ (* Buidling of the ASTA step by step with a special case for the last
+ step. Then add a top most state. Each function modifies asta. *)
let rec trans = function
| [s] -> trans_last s
| s :: tl -> trans_step s; trans tl
| [] -> ()
- and trans_init () = (* add THE top state *)
+ and trans_init () = (* add THE top most state *)
let top_st = Asta.new_state () in
let or_top =
- List.fold_left (fun acc x -> (`Left *+ x +| acc))
- Formula.true_ (Asta.top_states asta)
+ List.fold_left (fun acc x -> ((`Left *+ x) +| acc))
+ (Formula.false_) (Asta.top_states asta)
in
+ Asta.add_quer asta top_st;
+ Asta.init_top asta;
+ Asta.add_top asta top_st;
Asta.add_tr asta (top_st, Asta.any_label, or_top)
and trans_last (ax,test,pred) = (* a selecting state is needed *)
- ()
-
+ let fo_p = trans_pr pred in
+ let q,q' = Asta.new_state(), Asta.new_state() in
+ Asta.add_selec asta q';
+ Asta.add_quer asta q;
+ Asta.add_quer asta q';
+ Asta.add_top asta q;
+ Asta.add_top asta q';
+ Asta.add_bot asta q;
+ Asta.add_bot asta q';
+ let Simple lab = test in
+ let tr_selec = (q', lab, fo_p)
+ and tr_q = (q, Asta.any_label, form_propa_selec q q' ax) in
+ Asta.add_tr asta tr_selec;
+ Asta.add_tr asta tr_q
+
and trans_step (ax,test,pred) =
()
- and trans_pr p = ()
+ and trans_pr = function (* either we apply De Morgan rules
+ in xPath:parse or here *)
+ | Expr True -> Formula.true_
+ | Expr False -> Formula.false_
+ | Or (p_1,p_2) -> trans_pr(p_1) +| trans_pr(p_2)
+ | And (p_1,p_2) -> trans_pr(p_1) *& trans_pr(p_2)
+ | Not (Expr Path q) -> Formula.true_ (* todo *)
+ | Expr Path q -> Formula.true_ (* todo *)
+ | x -> print_predicate pr_er x; raise Not_core_XPath
+
+ and form_propa q = function
+ | Child -> `Right *+ q
+ | Descendant -> (`Left *+ q +| `Right *+ q)
+ | x -> print_axis pr_er x; raise Not_core_XPath
+ and form_propa_selec q q' = function
+ | Child -> `Right *+ q +| `Right *+ q'
+ | Descendant -> (`Left *+ q +| `Right *+ q) +| (`Left *+ q' +| `Right *+ q')
+ | x -> print_axis pr_er x; raise Not_core_XPath
+
in
match query with
- | Absolute steps -> trans_init(); trans steps; asta
- | AbsoluteDoS steps as x -> raise (Not_core_XPath x)
- | Relative steps as x -> raise (Not_core_XPath x)
+ | Absolute steps -> trans steps; trans_init(); asta
+ | AbsoluteDoS steps as x -> print pr_er x; raise Not_core_XPath
+ | Relative steps as x -> print pr_er x; raise Not_core_XPath