X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmisc%2FMetaGrammar.java;h=b1de3b1471a0138482a79f59093609ecf411bbde;hp=963a3177b81d046f5a5589952116a18e3ff023b9;hb=6ba9ea820f9626a7504da6cf442e2cef1601914f;hpb=017b5ed533ca298fe5ae1078e2a59da1d2d95ea2

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 963a317..b1de3b1 100644
--- a/src/edu/berkeley/sbp/misc/MetaGrammar.java
+++ b/src/edu/berkeley/sbp/misc/MetaGrammar.java
@@ -103,6 +103,9 @@ public class MetaGrammar extends StringWalker {
         return ret;
     }
 
+    // hack, this doens't really work if you're nesting
+    HashSet<Element> keep = new HashSet<Element>();
+
     public Sequence sequence(Object o, boolean lame) {
         return new PreSequence((Element[])Reflection.lub((Object[])o), null).buildSequence(null, lame, false);
     }
@@ -132,8 +135,9 @@ public class MetaGrammar extends StringWalker {
             carets.put(ret, s);
             dropAll.add(ret);
             return ret;
-        }
-        else if ("psx".equals(head)) return ((PreSequence)walk(tree, 0)).buildSequence();
+        } else if ("^^".equals(head)) {
+            return new Keep(walk(tree,0));
+        } else if ("psx".equals(head)) return ((PreSequence)walk(tree, 0)).buildSequence();
         else if ("nonTerminal".equals(head)) return getNonTerminal(string(tree.child(0)));
         else if ("::=".equals(head)) return nonTerminal(string(tree.child(0)), (Sequence[][])walk(tree, 1), false, false);
         else if ("=".equals(head)) return nonTerminal(string(tree.child(0)), (Sequence[][])walk(tree, 1), false, false);
@@ -167,6 +171,11 @@ public class MetaGrammar extends StringWalker {
         else return super.walk(tree);
     }
 
+    static class Keep {
+        final Object o;
+        public Keep(Object o) { this.o = o; }
+    }
+
     public String convertLabel(String label) { return label; }
 
     public Object walk(String tag, Object[] argo) {
@@ -251,10 +260,12 @@ public class MetaGrammar extends StringWalker {
             HashSet<Sequence> set = new HashSet<Sequence>();
             Element[] o2 = o==null ? new Element[0] : new Element[o.length];
             int nonDrop = 0;
+            int keeping = -1;
             if (o != null) {
                 int j = 0;
                 for(int i=0; i<o.length; i++) {
                     Object oi = o[i];
+                    if (oi instanceof Keep)    { keeping = j; oi = ((Keep)oi).o; }
                     if (oi==SELF)                    o2[j] = u.new Subset("(("+u+"))", set);
                     else                             o2[j] = (Element)oi;
 
@@ -273,10 +284,14 @@ public class MetaGrammar extends StringWalker {
             else if (tag!=null) ret = Sequence.rewritingSequence(tag, expansion, drops);
             else {
                 int idx = -1;
-                for(int i=0; i<expansion.length; i++)
-                    if (!drops[i])
-                        if (idx==-1) idx = i;
-                        else throw new Error("multiple non-dropped elements in sequence: " + Sequence.drop(expansion,false));
+                if (keeping != -1) {
+                    idx = keeping;
+                } else {
+                    for(int i=0; i<expansion.length; i++)
+                        if (!drops[i])
+                            if (idx==-1) idx = i;
+                            else throw new Error("multiple non-dropped elements in sequence: " + Sequence.drop(expansion,false));
+                }
                 if (idx != -1) ret = Sequence.singleton(expansion, idx);
                 else           ret = Sequence.drop(expansion, false);
             }
@@ -450,6 +465,9 @@ public class MetaGrammar extends StringWalker {
 
 
 
+
+
+
         // DO NOT EDIT STUFF BELOW: IT IS AUTOMATICALLY GENERATED
 new edu.berkeley.sbp.Tree(null, "gram", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "grammar", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "=", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "s", new edu.berkeley.sbp.Tree[] { })}),
         new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "::", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "g", new edu.berkeley.sbp.Tree[] { }),
@@ -854,15 +872,13 @@ new edu.berkeley.sbp.Tree(null, "gram", new edu.berkeley.sbp.Tree[] { new edu.be
         new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "?", new edu.berkeley.sbp.Tree[] { })})})})}),
         new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "s", new edu.berkeley.sbp.Tree[] { })})})})}),
-        new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "/", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { })})}),
+        new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { })})}),
         new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "Q", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "u", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "o", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "t", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "e", new edu.berkeley.sbp.Tree[] { }),
-        new edu.berkeley.sbp.Tree(null, "d", new edu.berkeley.sbp.Tree[] { })})})})}),
-        new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
-        new edu.berkeley.sbp.Tree(null, "s", new edu.berkeley.sbp.Tree[] { })})})})}),
+        new edu.berkeley.sbp.Tree(null, "d", new edu.berkeley.sbp.Tree[] { })})})})})}),
         new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "/", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "literal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "(", new edu.berkeley.sbp.Tree[] { })})}),
         new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "o", new edu.berkeley.sbp.Tree[] { }),
@@ -879,7 +895,11 @@ new edu.berkeley.sbp.Tree(null, "gram", new edu.berkeley.sbp.Tree[] { new edu.be
         new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "s", new edu.berkeley.sbp.Tree[] { })})})})}),
         new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "~", new edu.berkeley.sbp.Tree[] { })})}),
-        new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "e", new edu.berkeley.sbp.Tree[] { })})})})})})})})}),
+        new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "e", new edu.berkeley.sbp.Tree[] { })})})})})})}),
+        new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "::", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { }),
+        new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { })}),
+        new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "literal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "^", new edu.berkeley.sbp.Tree[] { })})}),
+        new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "e", new edu.berkeley.sbp.Tree[] { })})})})})})})})})}),
         new edu.berkeley.sbp.Tree(null, "=", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "o", new edu.berkeley.sbp.Tree[] { }),
         new edu.berkeley.sbp.Tree(null, "r", new edu.berkeley.sbp.Tree[] { }),
@@ -1102,3 +1122,6 @@ new edu.berkeley.sbp.Tree(null, "gram", new edu.berkeley.sbp.Tree[] { new edu.be
 
 
 
+
+
+