X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmisc%2FMetaGrammar.java;h=3501ee60fcbd375a4055af6cbe87ec54594740ac;hp=7b64f7066fa3242f536f20d6feef09d5a89ab758;hb=e2a835683bc6f2f873b17710ba85806720f88127;hpb=55b213d397cdc89a21905c9ca01d11405dbbf3ae

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 7b64f70..3501ee6 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();
@@ -71,36 +71,15 @@ public class MetaGrammar extends ReflectiveWalker {
         return n;
     }
 
-    public Object   _leftbrace_(PreSequence p) {
-        return nonTerminal("braced"+(anon++),
-                           new PreSequence[][] {
-                               new PreSequence[] {
-                                   new PreSequence(new Element[] { leftBrace(),
-                                                                   p.buildUnion(),
-                                                                   rightBrace()
-                                   })
-                               }
-                           },
-                           false,
-                           false);
-    }
-
-    public PreSequence ps2(Object[] o1, String s, Object[] o2) {
-        if (o1==null) o1 = new Object[0];
-        if (o2==null) o2 = new Object[0];
-        Object[] o3 = new Object[o1.length + o2.length + 1];
-        System.arraycopy(o1, 0, o3, 0, o1.length);
-        o3[o1.length] = string(s);
-        System.arraycopy(o2, 0, o3, o1.length+1, o2.length);
-        PreSequence ret = new PreSequence(o3, s);
-        ret.drops[o1.length] = o3.length>1;
+    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;
     }
 
@@ -135,6 +114,31 @@ public class MetaGrammar extends ReflectiveWalker {
         else if ("=>".equals(head)) { PreSequence p = (PreSequence)walk(tree, 0); p.tag = string(tree.child(1)); return p; }
         else if ("/".equals(head)) return ((PreSequence)walk(tree, 0)).sparse((Element)walk(tree, 1));
         else if ("ps".equals(head)) return new PreSequence((Element[])walk(tree, 0));
+        else if ("ps2".equals(head)) {
+            Object[] o1 = (Object[])walk(tree, 0);
+            String s = string(tree.child(1));
+            Object[] o2 = (Object[])walk(tree, 2);
+            if (o1==null) o1 = new Object[0];
+            if (o2==null) o2 = new Object[0];
+            Object[] o3 = new Object[o1.length + o2.length + 1];
+            System.arraycopy(o1, 0, o3, 0, o1.length);
+            o3[o1.length] = string(s);
+            System.arraycopy(o2, 0, o3, o1.length+1, o2.length);
+            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)) {
             boolean positive = "[".equals(head);
             Range[] rr = (Range[])walk(tree, 0);
@@ -149,6 +153,13 @@ 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 {