+// (C) 2006-2007 all rights reserved; see LICENSE file for BSD-style license
+
package edu.berkeley.sbp;
import java.io.*;
import java.util.*;
-import java.lang.reflect.*;
-import java.lang.ref.*;
-import edu.berkeley.sbp.*;
import edu.berkeley.sbp.util.*;
-/** a stream of tokens to be parsed */
+// FEATURE: Region implements Topology<Location<Tok>>
+
+/** <font color=purple>a stream of <tt>Token</tt>s to be parsed</font> */
public interface Input<Token> {
+ /** the current location within the input stream */
+ public Location<Token> getLocation();
+
/** returns the token just beyond the current location and advances beyond it */
- public Token next() throws IOException;
+ public Token next() throws IOException;
+
+ /** a short string describing where the input is coming from, such as a filename */
+ public String getName();
+
+ /** might called by Parser when it is done with the input */
+ public void close();
- /** returns the location the input stream is currently at */
- public Location getLocation();
+ /**
+ * <b>Optional:</b> <i>If possible</i>, this method will return a
+ * rendering of the input region (for example, if the input is a
+ * region of characters, it would be those characters) --
+ * otherwise, returns null. In any case, the string returned
+ * will be no more than <tt>maxLength</tt> characters long;
+ * typically ellipses will be inserted to perform truncation.
+ */
+ public abstract String showRegion(Region<Token> r, int maxLength);
+
+ /** <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> {
+
+ /** should return less than 80 chars 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();
+
+ }
+
}