checkpoint

[sbp.git] / src / edu / berkeley / sbp / misc / MetaGrammar.java

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 687d2d8..d385a55 100644 (file)
--- a/src/edu/berkeley/sbp/misc/MetaGrammar.java
+++ b/src/edu/berkeley/sbp/misc/MetaGrammar.java
@@ -55,7 +55,7 @@ public class MetaGrammar extends ReflectiveWalker {
     public Element     _rightparen_(Object e)                                         { return SELF; }
     public Element     _bang_(Element r)                                              { return r; }
     public Object      _caret_(String s)                                              { return new MyLift(s); }
-    public Object      _leftparen__rightparen_()                                      { return epsilon; }
+    public Object      _leftparen__rightparen_(Object o)                              { return epsilon; }
     public Union       nonTerminal(String s)                                          { return nonTerminal(s, null, false, false); }
     public Union       _colon__colon__equals_(String s, PreSequence[][] p)            { return nonTerminal(s, p, false, false); }
     public Union       _bang__colon__colon__equals_(String s, PreSequence[][] p)      { return nonTerminal(s, p, false, true); }
@@ -82,13 +82,24 @@ public class MetaGrammar extends ReflectiveWalker {
     }
 
     public Object   _backslash__leftbrace_(String s)      { return SELF; }
-    public Object   _leftbrace_(String s)                 { return SELF; }
-    public Object   _plus_(final Element r) { return Repeat.many1(r); }
+    public Object   _leftbrace_(PreSequence p) {
+        return nonTerminal("braced"+(anon++),
+                           new PreSequence[][] {
+                               new PreSequence[] {
+                                   new PreSequence(CharToken.leftBrace),
+                                   p,
+                                   new PreSequence(CharToken.rightBrace)
+                               }
+                           },
+                           false,
+                           false);
+    }
 
-    public PreSequence rewrite(Object[] o)                                            { return new PreSequence(o, null); }
-    public PreSequence _equals__greater_(Object[] o, String s)                        { return new PreSequence(o, s); }
+    public Object   _plus_(final Element r)                    { return Repeat.many1(r); }
+    public PreSequence rewrite(Object[] o)                     { return new PreSequence(o, null); }
+    public PreSequence _equals__greater_(Object[] o, String s) { return new PreSequence(o, s); }
     public PreSequence seq(Object[] o, Object sep, String tag) { return new PreSequence(sep==null ? o : _slash_(o, sep), tag); }
-    public Object[] seq(Object[] o) { return o; }
+    public Object[] seq(Object[] o)                            { return o; }
     public Object[] _slash_(Object[] o, Object sep) {
         if (o.length <= 1) return o;
         Object[] ret = new Object[o.length * 2 - 1];
@@ -141,6 +152,8 @@ public class MetaGrammar extends ReflectiveWalker {
         public /*final*/ String tag;
         public final Object[] o;
 
+        public PreSequence(Object o) { this(new Object[] { o }, null); }
+        public PreSequence(Object[] o) { this(o, null); }
         public PreSequence(Object[] o, String tag) { this.o = o; this.tag = tag; }
         boolean[] drops = null;
         public Union    buildUnion() {
@@ -154,6 +167,7 @@ public class MetaGrammar extends ReflectiveWalker {
             for(Sequence s : not) u.add(s);
             HashSet<Sequence> set = new HashSet<Sequence>();
             Element[] o2 = o==null ? new Element[0] : new Element[o.length];
+            int nonDrop = 0;
             if (o != null) {
                 drops = new boolean[o.length];
                 int j = 0;
@@ -162,10 +176,11 @@ public class MetaGrammar extends ReflectiveWalker {
                     if (oi instanceof MyDrop)      { oi = ((MyDrop)oi).o; drops[j] = true; }
 
                     if (oi==SELF)                    o2[j] = u.new Subset("(("+u+"))", set);
-                    else if (oi instanceof MyLift) { o2[j] = CharToken.string(tag = ((MyLift)oi).s); drops[j] = true; }
+                    else if (oi instanceof MyLift) { o2[j] = CharToken.string(tag = ((MyLift)oi).s); drops[j] = o.length>1; }
                     else                             o2[j] = (Element)oi;
 
                     if (MetaGrammar.dropAll.contains(o2[j])) drops[j] = true;
+                    nonDrop += drops[j] ? 0 : 1;
                     o2[j] = o2[j];
                     j++;
                 }