From c0b6bf74a7df6f1c8951525cab015fda4c788a9d Mon Sep 17 00:00:00 2001
From: kim <kim@3cdefd35-fc62-479d-8e8d-bae585ffb9ca>
Date: Thu, 19 Jan 2012 09:48:52 +0000
Subject: [PATCH] Add backward moves in the syntax of the automaton.

git-svn-id: svn+ssh://idea.nguyen.vg/svn/sxsi/trunk/xpathcomp@1186 3cdefd35-fc62-479d-8e8d-bae585ffb9ca
---
 src/formula.ml  | 4 +++-
 src/formula.mli | 8 ++++----
 src/runtime.ml  | 1 +
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/formula.ml b/src/formula.ml
index 16db6d5..3b344e7 100644
--- a/src/formula.ml
+++ b/src/formula.ml
@@ -6,7 +6,7 @@ type 'hcons expr =
   | False | True
   | Or of 'hcons * 'hcons
   | And of 'hcons * 'hcons
-  | Atom of ([ `Left | `Right ] * bool * State.t)
+  | Atom of ([ `Left | `Right | `Epsilon ] * bool * State.t)
   | Pred of Tree.Predicate.t
 
 type 'hcons node = {
@@ -78,6 +78,7 @@ let rec print ?(parent=false) ppf f =
 	  match  dir with
 	    | `Left ->  Pretty.down_arrow, Pretty.subscript 1
 	    | `Right -> Pretty.down_arrow, Pretty.subscript 2
+	    | `Epsilon -> Pretty.epsilon, ""
 	in
 	  fprintf fmt "%s%s" a_str d_str;
 	  State.print fmt s;
@@ -109,6 +110,7 @@ let atom_ d p s =
   let ss = match d with
     | `Left -> (si,StateSet.empty,si),empty_triple
     | `Right -> empty_triple,(si,StateSet.empty,si)
+    | `Epsilon -> empty_triple, empty_triple
   in fst (cons (Atom(d,p,s)) (Atom(d,not p,s)) ss ss 1 1)
 
 let pred_ p =
diff --git a/src/formula.mli b/src/formula.mli
index 88763ee..1dd05e2 100644
--- a/src/formula.mli
+++ b/src/formula.mli
@@ -3,7 +3,7 @@ type 'a expr =
     | True
     | Or of 'a * 'a
     | And of 'a * 'a
-    | Atom of ([ `Left |`Right ] * bool * State.t)
+    | Atom of ([ `Left |`Right | `Epsilon ] * bool * State.t)
     | Pred of Tree.Predicate.t
 
 type t
@@ -23,7 +23,7 @@ val is_false : t -> bool
 val true_ : t
 val false_ : t
 val atom_ :
-  [ `Left | `Right ] -> bool -> StateSet.elt -> t
+  [ `Left | `Right | `Epsilon ] -> bool -> StateSet.elt -> t
 val pred_ : Tree.Predicate.t -> t
 val not_ : t -> t
 val or_ : t -> t -> t
@@ -37,7 +37,7 @@ module Infix : sig
   val ( +| ) : t -> t -> t
   val ( *& ) : t -> t -> t
   val ( *+ ) :
-    [ `Left | `Right ] -> StateSet.elt -> t
+    [ `Left | `Right | `Epsilon ] -> StateSet.elt -> t
   val ( *- ) :
-    [ `Left | `Right ] -> StateSet.elt -> t
+    [ `Left | `Right | `Epsilon ] -> StateSet.elt -> t
 end
diff --git a/src/runtime.ml b/src/runtime.ml
index c355f5e..e32812b 100644
--- a/src/runtime.ml
+++ b/src/runtime.ml
@@ -24,6 +24,7 @@ module Make (U : ResJIT.S) : S with type result_set = U.NS.t =
 	  | Formula.Atom (`Right, b, q) ->
 	      Formula.of_bool(b == (StateSet.mem q s2)),
 	      if b && StateSet.mem q auto.topdown_marking_states then [ResJIT.RIGHT q] else []
+	  | Formula.Atom (`Epsilon, _, _) -> assert false
 
 	  | Formula.Or(f1, f2) ->
 	      let b1, i1 = loop f1 in
-- 
2.17.1