X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FWalk.java;h=380d09bda11236d3d4e30e1fec9f19da314cc5b6;hp=22ef52e66e4214b8f5dfdaab44522cf8ab1144ab;hb=e5d6a50df43fa50f217b30b0959a1d39f65b621c;hpb=21da21b94e794fa4d7c7207327764895d92ea528

diff --git a/src/edu/berkeley/sbp/Walk.java b/src/edu/berkeley/sbp/Walk.java
index 22ef52e..380d09b 100644
--- a/src/edu/berkeley/sbp/Walk.java
+++ b/src/edu/berkeley/sbp/Walk.java
@@ -85,7 +85,7 @@ abstract class Walk<T> {
         public Topology<Tok> walkAtom(Atom r)          { cs = cs.union(r); return cs; }
     }
 
-    class First<Tok extends Token> extends WalkTokenSet<Tok> {
+    static class First<Tok extends Token> extends WalkTokenSet<Tok> {
         public First(Topology<Tok> cs, Walk.Cache cache) { super(cs, cache); }
         public Topology<Tok> sequence(Sequence seq) {
             for(Position p = seq.firstp(); p!=null && !p.isLast(); p = p.next()) {
@@ -129,7 +129,7 @@ abstract class Walk<T> {
                 Sequence a = (Sequence)x;
                 Position mp = null;
                 for(Position pos = a.firstp(); pos != null && !pos.isLast(); pos = pos.next()) {
-                    if (matched) cs = cs.union(new First<Tok>(cs.empty(), c).walk(pos.element()));
+                    if (matched) cs = cs.union(c.first(pos.element(), cs.empty()));
                     if (pos.isLast()) { matched = (matched && pos.element().possiblyEpsilon(c)); continue; }
                     boolean good = false;
                     if (e instanceof Atom) {
@@ -172,5 +172,8 @@ abstract class Walk<T> {
         public HashMap<Element,Topology> follow = new HashMap<Element,Topology>();
         public HashMapBag<Element,Element>  ys = new HashMapBag<Element,Element>();
         public HashMap<Element,Topology> atoms = new HashMap<Element,Topology>();
+        public <Tok extends Token> Topology<Tok> first(Element e, Topology<Tok> empty) {
+            return new Walk.First<Tok>(empty, this).walk(e);
+        }
     }
 }