X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmisc%2FMetaGrammar.java;h=49befee1a7c20583f49a2ef78bdc78b06131e005;hp=2751db707fb12e7a8908ae363e2a52b69439ed8b;hb=4c5cadfb5604449d04e2cdaaae7b9a61795c9044;hpb=5fbd1d712d38b88153a824160322050da6c5e184

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 2751db7..49befee 100644
--- a/src/edu/berkeley/sbp/misc/MetaGrammar.java
+++ b/src/edu/berkeley/sbp/misc/MetaGrammar.java
@@ -4,7 +4,7 @@ import edu.berkeley.sbp.*;
 import java.util.*;
 import java.io.*;
 
-public class MetaGrammar extends ReflectiveWalker {
+public class MetaGrammar extends StringWalker {
 
     public static Union make() throws Exception {
         return ((MetaGrammar)new MetaGrammar().walk(meta)).done();
@@ -15,7 +15,7 @@ public class MetaGrammar extends ReflectiveWalker {
         return ret.toString();
     }
 
-    private static HashSet<Element> dropAll = new HashSet<Element>();
+    public /*private*/ static HashSet<Element> dropAll = new HashSet<Element>();
 
     // Statics //////////////////////////////////////////////////////////////////////////////
 
@@ -51,6 +51,7 @@ public class MetaGrammar extends ReflectiveWalker {
 
     // MetaGrammar //////////////////////////////////////////////////////////////////////////////
 
+    public Union       nonTerminal(String str) { return nonTerminal(str, null, false, false); }
     public Union       nonTerminal(String str, PreSequence[][] s, boolean synthetic, boolean dropAll) {
         Union n = str.equals(startSymbol) ? g : nt.get(str);
         if (n == null) nt.put(str, n = new Union(str, synthetic));
@@ -71,10 +72,15 @@ public class MetaGrammar extends ReflectiveWalker {
         return n;
     }
 
+    public String string(Iterable<Tree<String>> children) {
+        String ret = "";
+        for(Tree<String> t : children) ret += string(t);
+        return ret;
+    }
     public String string(Tree<String> tree) {
         String ret = "";
         if (tree.head()!=null) ret += tree.head();
-        for(Tree<String> t : tree.children()) ret += string(t);
+        ret += string(tree.children());
         return ret;
     }
 
@@ -122,19 +128,7 @@ public class MetaGrammar extends ReflectiveWalker {
             PreSequence ret = new PreSequence(o3, s);
             ret.drops[o1.length] = o3.length>1;
             return ret;
-        } else if ("{".equals(head))
-            return nonTerminal("braced"+(anon++),
-                               new PreSequence[][] {
-                                   new PreSequence[] {
-                                       new PreSequence(new Element[] { leftBrace(),
-                                                                       ((PreSequence)walk(tree, 0)).buildUnion(),
-                                                                       rightBrace()
-                                       })
-                                   }
-                               },
-                               false,
-                               false);
-        else if ("[".equals(head) || "[~".equals(head)) {
+        } else if ("[".equals(head) || "[~".equals(head)) {
             boolean positive = "[".equals(head);
             Range[] rr = (Range[])walk(tree, 0);
             Range.Set ret = positive ? new Range.Set() : new Range.Set(new Range(true, true));
@@ -148,6 +142,13 @@ public class MetaGrammar extends ReflectiveWalker {
     }
 
 
+    public Object walk(String tag, Object[] argo) {
+        if (argo.length==0) return super.walk(tag, argo);
+        if (argo==null) return tag;
+        if (tag==null || "".equals(tag)) return argo;
+        return super.walk(tag, argo);
+    }
+
     //////////////////////////////////////////////////////////////////////////////
 
     public class PreSequence {