X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FInput.java;h=ac2c486e94db2cef4490805c1de49911b62227c1;hp=be41cbebeff1af501c5a65d25c5318a14f1210e9;hb=2afdfe14e78fa0597186614937c679a09d74ecdf;hpb=ac3843911c47a601ffd679d2e075b519d3a18d6a

diff --git a/src/edu/berkeley/sbp/Input.java b/src/edu/berkeley/sbp/Input.java
index be41cbe..ac2c486 100644
--- a/src/edu/berkeley/sbp/Input.java
+++ b/src/edu/berkeley/sbp/Input.java
@@ -1,56 +1,66 @@
+// (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();
 
-    /** returns the location the input stream is currently at */
-    public Location<Token> getLocation();
+    /** might called by Parser when it is done with the input */
+    public void close();
+
+    /**
+     *  <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 <i>between tokens<i> in the input stream */
-    public static interface Location<Tok> extends Comparable<Location> {
         public String toString();
 
-        /** an implementation of Location for a cartesian grid (row, col) */
-        public static class Cartesian<Tok> implements Location<Tok>, Comparable<Location> {
-            protected final int row;
-            protected final int col;
-            public String toString() { return row+":"+col; }
-            public int getCol() { return col; }
-            public int getRow() { return row; }
-            public Cartesian(int col, int row) { this.row = row; this.col = col; }
-            public int compareTo(Location loc) throws ClassCastException {
-                if (!(loc instanceof Cartesian)) throw new ClassCastException();
-                Cartesian<Tok> c = (Cartesian<Tok>)loc;
-                if (row < c.row) return -1;
-                if (row > c.row) return  1;
-                if (col < c.col) return -1;
-                if (col > c.col) return  1;
-                return 0;
-            }
-        }
+        /** the location following this one */
+        public Location next();
+
+        /** the location preceding this one */
+        public Location prev();
     }
 
-    public static class Region<Loc extends Location> /* implements Topology<Location<Tok>> */ {
-        public final Loc start;
-        public final Loc 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");
-            }
-        }
+    /** <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();
+
     }
+
 }