checkpoint

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

diff --git a/src/edu/berkeley/sbp/Atom.java b/src/edu/berkeley/sbp/Atom.java
index 306e126..daa3d49 100644 (file)
--- a/src/edu/berkeley/sbp/Atom.java
+++ b/src/edu/berkeley/sbp/Atom.java
@@ -7,12 +7,24 @@ import edu.berkeley.sbp.util.*;
 import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.*;
 
-/** <font color=green>an element which matches exactly one input token</font> */
-public abstract class Atom<T> extends Element implements Topology<Atom<T>> {
+/**
+ *  <font color=green>an element which matches some set of one-token-long input strings</font>.
+ *
+ *  <p>
+ *  This class is a topology over itself (yes, that's sort of Frege'd
+ *  up) so that Atoms can be intersected and unioned with each other
+ *  to result in other Atom<Token>'s (rather than raw Topology<Token>'s, which
+ *  are not Elements).  If you want the latter, use the
+ *  getTokenTopology() method.
+ *  </p>
+ */
+public abstract class Atom<Token> extends Element implements Topology<Atom<Token>> {
 
-    public  abstract Topology<T>  underlying();
-    public  abstract String       toString();
-    public           StringBuffer toString(StringBuffer sb) { sb.append(this); return sb; }
+    /** the set (topology) of tokens that can match this element */
+    public abstract Topology<Token>  getTokenTopology();
+
+    StringBuffer toString(StringBuffer sb) { sb.append(this); return sb; }
 
 }
 
+