+// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
+
package edu.berkeley.sbp;
import java.io.*;
import java.util.*;
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 {
+/** <font color=purple>a stream of <tt>Token</tt>s to be parsed</font> */
+public interface Input<Token> {
- /** this is declared abstract as a way of forcing subclasses to provide a thoughtful implementation */
- public abstract String toString();
+ /** returns the token just beyond the current location and advances beyond it */
+ public Token next() throws IOException;
- /** a sequence of input tokens; returns null when EOF is reached */
- public static interface Stream<Tok> {
- public Tok next(int numstates, int resets, int waits) throws IOException;
- public abstract Location getLocation();
- }
+ /** returns the location the input stream is currently at */
+ public Location<Token> getLocation();
+
+ /** should return a short string describing where the input is coming from */
+ public String getName();
+
+ /**
+ * <b>Optional:</b> <i>If possible</i>, this method will return a
+ * <60 char long rendering of the input region (for example, if
+ * the input is a region of characters, it would be those
+ * characters, possibly with ellipses in the middle to truncate
+ * the length) -- otherwise, returns null.
+ */
+ public abstract String showRegion(Region<Token> r);
+
+ /** <font color=purple>a location (position) in the input stream -- <i>between tokens</i></font> */
+ public static interface Location<Token> extends Comparable<Location> {
+
+ /** return the region between this location and <tt>loc</tt> */
+ public Region<Token> createRegion(Location<Token> loc);
- /** a location *between tokens* in the input stream */
- public static interface Location {
public String toString();
+
+ /** the location following this one */
+ public Location next();
+
+ /** the location preceding this one */
+ public Location prev();
}
+
+ /** <font color=purple>a contiguous set of <tt>Location</tt>s</font> */
+ public static interface Region<Token> /* implements Topology<Location<Tok>> */ {
+
+ /**
+ * the toString() method of Region should return a <80char
+ * "rendition" of the input region, if possible
+ */
+ public abstract String toString();
+
+ /** The location of the start of this region */
+ public abstract Location<Token> getStart();
+
+ /** The location of the end of this region */
+ public abstract Location<Token> getEnd();
+
+ }
+
}