checkpoint

[sbp.git] / src / edu / berkeley / sbp / Repeat.java

diff --git a/src/edu/berkeley/sbp/Repeat.java b/src/edu/berkeley/sbp/Repeat.java
index 9cce700..b7e7e39 100644 (file)
--- a/src/edu/berkeley/sbp/Repeat.java
+++ b/src/edu/berkeley/sbp/Repeat.java
@@ -8,11 +8,12 @@ import java.lang.reflect.*;
 import java.lang.ref.*;
 
 /** currently this class exports only static methods to create repetitions; there are no public instance methods or constructors */
-/* FIXME make private again */ public class Repeat extends Union {
+class Repeat extends Union {
 
+    public Repeat(final Element e, boolean zeroOkay, boolean manyOkay, Object tag) {
+        this(e, zeroOkay, manyOkay, null, false, tag); }
     public Repeat(final Element e, boolean zeroOkay, boolean manyOkay, final Element separator, Object tag) {
-        this(e, zeroOkay, manyOkay, separator, false, tag);
-    }
+        this(e, zeroOkay, manyOkay, separator, false, tag); }
     protected Repeat(final Element e, boolean zeroOkay, boolean manyOkay, final Element separator, boolean maximal, Object tag) {
         super(e+(!manyOkay ? "?" : (zeroOkay ? (maximal ? "**" : "*") : (maximal ? "++" : "+")))+(separator==null?"":("/"+separator)), true);
         if (zeroOkay) {
@@ -34,13 +35,21 @@ import java.lang.ref.*;
             if (zeroOkay && separator != null)
                 throw new RuntimeException("cannot create a maximal repetition of zero or more items with a separator (yet): " + this);
             for(Sequence s : this)
-                s.follow = new edu.berkeley.sbp.misc.MetaGrammar.Invert(separator);
+                s.follow = new Invert(separator);
         }
         public Maximal(final Atom e, boolean zeroOkay, boolean manyOkay, Object tag) {
             super(e, zeroOkay, manyOkay, null, true, tag);
             for(Sequence s : this)
-                s.follow = new edu.berkeley.sbp.misc.MetaGrammar.Invert(e);
+                s.follow = new Invert(e);
         }
     }
 
+
+    /** an atom which tracks the inverse of some other atom */
+    private static class Invert<T extends Input> extends Atom<T> {
+        private final Atom<T> a;
+        public Invert(Atom<T> a) { this.a = a; }
+        public Topology<T> top() { return a.complement(); }
+        public String toString() { return "~"+a; }
+    }
 }