X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FRepeat.java;h=c85bfc6497dd140ab22b891e0e00a37e47a8c151;hb=aaa5d101e054dc548e7ef7831b1fcb7913a4d4d4;hp=48681355013875d3dc697283edf7181b7c9ebf5e;hpb=fa858dc4acddd3e32126ff2558e0860315a84758;p=sbp.git

diff --git a/src/edu/berkeley/sbp/Repeat.java b/src/edu/berkeley/sbp/Repeat.java
index 4868135..c85bfc6 100644
--- a/src/edu/berkeley/sbp/Repeat.java
+++ b/src/edu/berkeley/sbp/Repeat.java
@@ -10,16 +10,22 @@ import java.lang.ref.*;
 /** currently this class exports only static methods to create repetitions; there are no public instance methods or constructors */
 class Repeat extends Union {
 
-    Repeat(final Element e, boolean zeroOkay, boolean manyOkay, final Element separator, boolean maximal) {
-        this(e, zeroOkay, manyOkay, separator, maximal, null); }
-    Repeat(final Element e, boolean zeroOkay, boolean manyOkay, final Element separator, boolean maximal, Object tag) {
+    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); }
+    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) {
+        if (zeroOkay && !manyOkay) {
             add(new Sequence.Constant.Empty());
-            if (manyOkay) add(new Sequence.Singleton(Sequence.many1(e, separator)));
-            else          add(new Sequence.Singleton(e));
+            add(new Sequence.Singleton(e));
+            return;
+        }
+        if (zeroOkay) {
+            add(new Sequence.RewritingSequence(tag, new Element[] { }, null));
+            //add(new Sequence.Constant.Empty());
+            // FUGLY
+            add(new Sequence.Singleton(Sequence.many1(e, separator, tag)));
         } else {
             add(new Sequence.RewritingSequence(tag, new Element[] { e }, null));
             if (separator==null)
@@ -27,6 +33,29 @@ class Repeat extends Union {
             else
                 add(new Sequence.Unwrap(new Element[] { e, separator,      Repeat.this }, tag, new boolean[] { false, true, false }));
         }
-        if (maximal) for(Sequence s : this) s.noFollow = separator==null ? e : separator;
+    }
+
+    public static class Maximal extends Repeat {
+        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; }
     }
 }