checkpoint

[sbp.git] / src / edu / berkeley / sbp / chr / CharRange.java

diff --git a/src/edu/berkeley/sbp/chr/CharRange.java b/src/edu/berkeley/sbp/chr/CharRange.java
index 8952536..78f2057 100644 (file)
--- a/src/edu/berkeley/sbp/chr/CharRange.java
+++ b/src/edu/berkeley/sbp/chr/CharRange.java
@@ -19,8 +19,9 @@ public class CharRange extends Atom<Character> {
 
     public static final char left       = (char)9998;
     public static final char right      = (char)9999;
-    public static final Atom leftBrace  = new CharRange(left,left)   { public String toString() { return "{"; } };
-    public static final Atom rightBrace = new CharRange(right,right) { public String toString() { return "}"; } };
+    public static final Atom leftBrace  = new CharRange(left,left)   { public String toString() { return "[{]"; } };
+    public static final Atom rightBrace = new CharRange(right,right) { public String toString() { return "[}]"; } };
+    public static final Atom braces     = new CharRange(left,right)   { public String toString() { return "[{}]"; } };
 
     public static Atom set(Range.Set r) { return new CharRange(new CharTopology(r)); }
 
@@ -29,7 +30,7 @@ public class CharRange extends Atom<Character> {
     /** returns an element which exactly matches the string given */
     public static Element string(String s) { return string(s, true); }
     public static Element string(String s, boolean share) {
-        if (share && s.length() == 0) return Union.epsilon;
+        if (share && s.length() == 0) return epsilon;
         final String escapified = "\""+StringUtil.escapify(s, "\"\r\n\\")+"\"";
         Element ret;
         if (share && s.length() == 1) {
@@ -47,4 +48,6 @@ public class CharRange extends Atom<Character> {
         return ret;
     }
 
+    private static Union epsilon = new Union("()");
+    static { epsilon.add(Sequence.empty); }
 }