X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FRepeat.java;h=b7e7e39703f54e35c426427f6e804f076cc18648;hb=b205c5ee125119b0372328b70e8a66164df18fd0;hp=c4e948627cf8903076ed3feb85796abf7dad5714;hpb=74fc87dc827975ed4e9e411bb169a5f5bfb1010f;p=sbp.git

diff --git a/src/edu/berkeley/sbp/Repeat.java b/src/edu/berkeley/sbp/Repeat.java
index c4e9486..b7e7e39 100644
--- a/src/edu/berkeley/sbp/Repeat.java
+++ b/src/edu/berkeley/sbp/Repeat.java
@@ -8,15 +8,14 @@ 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 (maximal && zeroOkay && separator != null)
-            throw new RuntimeException("cannot create a maximal repetition of zero or more items with a separator (yet): " + this);
         if (zeroOkay) {
             add(new Sequence.Constant.Empty());
             if (manyOkay) add(new Sequence.Singleton(Sequence.many1(e, separator)));
@@ -28,16 +27,29 @@ import java.lang.ref.*;
             else
                 add(new Sequence.Unwrap(new Element[] { e, separator,      Repeat.this }, tag, new boolean[] { false, true, false }));
         }
-        // FIXME: hack!
-        if (maximal)
-            for(Sequence s : this)
-                s.follow = new edu.berkeley.sbp.misc.MetaGrammar.Invert(new edu.berkeley.sbp.misc.MetaGrammar.Infer(separator==null ? e : separator));
     }
 
     public static class Maximal extends Repeat {
-        public Maximal(final Element e, boolean zeroOkay, boolean manyOkay, final Element separator, Object tag) {
+        public Maximal(final Element e, boolean zeroOkay, boolean manyOkay, final Atom separator, Object tag) {
             super(e, zeroOkay, manyOkay, separator, true, tag);
+            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 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 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; }
+    }
 }