added StringToken

darcs-hash:20051225102852-5007d-9bd3d55edabd4107e8d3fe0b712b65483a9fe313.gz

diff --git a/src/edu/berkeley/sbp/misc/StringToken.java b/src/edu/berkeley/sbp/misc/StringToken.java
new file mode 100644 (file)
index 0000000..fac11ab
--- /dev/null
+++ b/src/edu/berkeley/sbp/misc/StringToken.java
@@ -0,0 +1,42 @@
+package edu.berkeley.sbp.misc;
+import java.io.*;
+import java.util.*;
+import java.lang.reflect.*;
+import java.lang.ref.*;
+import edu.berkeley.sbp.*;
+import edu.berkeley.sbp.*;
+import edu.berkeley.sbp.util.*;
+import edu.berkeley.sbp.*;
+
+/** an implementation of Token for streams of Java <tt>char</tt> values */
+public class StringToken implements Token {
+
+    public static final StringToken left = new StringToken(null, null) { public boolean equals(Object o) { return this==o; } };
+    public static final StringToken right = new StringToken(null, null) { public boolean equals(Object o) { return this==o; } };
+
+    public static final Atom leftBrace  = new Atom(new DiscreteTopology<StringToken>(left)) { public String toString() { return "{"; } };
+    public static final Atom rightBrace = new Atom(new DiscreteTopology<StringToken>(right)) { public String toString() { return "}"; } };
+
+    private static class StringAtom extends Atom {
+        private String s;
+        public StringAtom(String s) { super(new DiscreteTopology<StringToken>(new StringToken(s, null))); this.s = s; }
+        public String toString() { return "[atom \""+s+"\"]"; }
+    }
+
+    /** returns an element which exactly matches the string given */
+    public static Element string(String s) {
+        return new StringAtom(s);
+    }
+
+    public static Topology<StringToken> top() { return new DiscreteTopology<StringToken>(); }
+
+    public final String s;
+    public final Location location;
+    private StringToken(String s, Location loc)    { this.s = s; this.location = loc; }
+    public String result()                         { return s; }
+    public Location getLocation()                  { return location; }
+    public String  toString()                      { return "\'"+StringUtil.escapify(s)+"\'"; }
+
+    public boolean equals(Object o) { return o!=null && o instanceof StringToken && s.equals(((StringToken)o).s); }
+    public int     hashCode()       { return s==null ? 0 : s.hashCode(); }
+}