X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FAtom.java;h=6c7a25ee59c02ad74a4f44658c71fd8a7f7c9e11;hb=439a7ad1815292b659ebe50fba55aefd73f4a68f;hp=3b7ce1fa558692f388fc21ed6fd89f6587591eed;hpb=6b53048f4413f3c618acc3581d0b4f60a236a9bc;p=sbp.git

diff --git a/src/edu/berkeley/sbp/Atom.java b/src/edu/berkeley/sbp/Atom.java
index 3b7ce1f..6c7a25e 100644
--- a/src/edu/berkeley/sbp/Atom.java
+++ b/src/edu/berkeley/sbp/Atom.java
@@ -8,24 +8,15 @@ import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.*;
 
 /** an element which matches exactly one input token */
-public abstract class Atom<T extends Token> extends Element implements Topology<T> {
+public abstract class Atom<T> extends Element implements Topology<T> {
 
     protected abstract Topology<T> top();
-
-    public Topology toAtom() { return this; }
-
-    /** equality is based on the underlying <tt>Topology</tt> */
-    public int hashCode() { return top().hashCode(); }
-    
-    /** equality is based on the underlying <tt>Topology</tt> */
-    public boolean equals(Object o) { return o != null && o instanceof Atom && ((Atom)o).top().equals(top()); }
-
-    /** declared abstract to force subclasses to override it in a useful manner */
-    public abstract String toString();
+    public    abstract String       toString();
+    public             StringBuffer toString(StringBuffer sb) { sb.append(this); return sb; }
 
     // Topology Thunks //////////////////////////////////////////////////////////////////////////////
 
-    public Topology<T>       unwrap() { return top().unwrap(); }
+    public Topology<T>       unwrap()                   { return top().unwrap(); }
     public Topology<T>       empty()                    { return top().empty(); }
     public boolean           contains(T v)              { return top().contains(v); }
     public Topology<T>       intersect(Topology<T> t)   { return top().intersect(t); }
@@ -34,22 +25,20 @@ public abstract class Atom<T extends Token> extends Element implements Topology<
     public Topology<T>       complement()               { return top().complement(); }
     public boolean           disjoint(Topology<T> t)    { return top().disjoint(t); }
     public boolean           containsAll(Topology<T> t) { return top().containsAll(t); }
-
-    // Subclasses //////////////////////////////////////////////////////////////////////////////
-
-    public static class Infer<T extends Token> extends Atom<T> {
-        private final Element e;
-        public Infer(Element e) { this.e = e; }
-        public Topology<T> top() { return (Topology<T>)e.toAtom(); }
-        public String toString() { return e.toString(); }
-    }
-    
-    public static class Invert<T extends Token> extends Atom<T> {
-        private final Atom<T> a;
-        public Invert(Atom<T> a) { this.a = a; }
-        public Topology<T> top() { return ((Topology<T>)a.top()).complement(); }
-        public String toString() { return "~"+a; }
+    public int               hashCode()                 { return top().hashCode(); }
+    public boolean           equals(Object o)           { return o != null && o instanceof Atom && ((Atom)o).top().equals(top()); }
+
+    /** if all expressions matching <tt>e</tt> are exactly one token
+     *  long, <b>attempt to</b> return an Atom representing that token
+     *  (undecidable in general; only works in trivial cases)
+     */
+    public static Topology toAtom(Element e) {
+        if (e instanceof Atom) return (Atom)e;
+        if (e instanceof Sequence) return ((Sequence)e).toAtom();
+        Topology ret = null;
+        for(Sequence s : (Union)e)
+            ret = ret==null ? toAtom(s) : ret.union(s.toAtom());
+        return ret;
     }
-    
 }