add maxLength argument to Input.showRegion()

[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 c16947d..bf0d50d 100644 (file)
--- a/src/edu/berkeley/sbp/Input.java
+++ b/src/edu/berkeley/sbp/Input.java
@@ -16,6 +16,19 @@ public interface Input<Token> {
 
     /** 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
+     *  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> {
@@ -24,10 +37,29 @@ public interface Input<Token> {
         public Region<Token> createRegion(Location<Token> loc);
 
         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();
+
     }
 
 }