checkpoint

[sbp.git] / src / edu / berkeley / sbp / meta / MetaGrammarBindings.java

diff --git a/src/edu/berkeley/sbp/meta/MetaGrammarBindings.java b/src/edu/berkeley/sbp/meta/MetaGrammarBindings.java
index 2866107..8be2fba 100644 (file)
--- a/src/edu/berkeley/sbp/meta/MetaGrammarBindings.java
+++ b/src/edu/berkeley/sbp/meta/MetaGrammarBindings.java
@@ -212,7 +212,17 @@ public class MetaGrammarBindings {
     public static @bind.as("{")           class XTree                 extends El {
         public @bind.arg Seq body;
         public Element build(MetaGrammar.Context cx) {
-            throw new Error();
+            Union u = new Union();
+            Sequence s = body.build(cx, u, false);
+            Union u2 = new Union();
+            u2.add(Sequence.singleton(new Element[] {
+                CharRange.leftBrace,
+                cx.get("ws"),
+                u,
+                cx.get("ws"),
+                CharRange.rightBrace
+            }, 2));
+            return u2;
         }
     }