checkpoint

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

diff --git a/src/edu/berkeley/sbp/Input.java b/src/edu/berkeley/sbp/Input.java
index d8374cd..407d843 100644 (file)
--- a/src/edu/berkeley/sbp/Input.java
+++ b/src/edu/berkeley/sbp/Input.java
@@ -6,16 +6,33 @@ import java.lang.ref.*;
 import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.util.*;
 
-/** a token of input -- note that this represents an <i>actual input token</i> rather than an <tt>Element</tt> which <i>matches</i> a token */
-public interface Input<Tok> {
+/** a stream of tokens to be parsed */
+public interface Input<Token> {
 
-    public Tok next(int numstates, int resets, int waits) throws IOException;
-    public abstract Location getLocation();
+    /** returns the token just beyond the current location and advances beyond it */
+    public Token           next() throws IOException;
 
-    /** a location *between tokens* in the input stream */
-    public static interface Location {
+    /** returns the location the input stream is currently at */
+    public Location<Token> getLocation();
+
+    /** a location <i>between tokens<i> in the input stream */
+    public static interface Location<Tok> extends Comparable<Location> {
         public String toString();
     }
+
+    public static class Region<Loc extends Location> /* implements Topology<Location<Tok>> */ {
+        public final Loc start;
+        public final Loc end;
+        public String toString() { return start+"-"+end; }
+        public Region(Loc a, Loc b) {
+            switch(a.compareTo(b)) {
+                case -1:
+                case  0: start=a; end=b; return;
+                case  1: start=b; end=a; return;
+                default: throw new Error("impossible");
+            }
+        }
+    }
 }