convered maximal to use character lookahead

[sbp.git] / src / edu / berkeley / sbp / tib / Tib.java

diff --git a/src/edu/berkeley/sbp/tib/Tib.java b/src/edu/berkeley/sbp/tib/Tib.java
index 200544a..39f6071 100644 (file)
--- a/src/edu/berkeley/sbp/tib/Tib.java
+++ b/src/edu/berkeley/sbp/tib/Tib.java
@@ -289,21 +289,30 @@ public class Tib implements Token.Stream<CharToken> {
 
     public static class Grammar extends MetaGrammar {
         private int anon = 0;
 
     public static class Grammar extends MetaGrammar {
         private int anon = 0;

+        private final Element ws = Repeat.maximal0(nonTerminal("w"));
+        public Grammar() { dropAll.add(ws); }

         public Object walk(Tree<String> tree) {
             String head = tree.head();
             if (tree.numChildren()==0) return super.walk(tree);
         public Object walk(Tree<String> tree) {
             String head = tree.head();
             if (tree.numChildren()==0) return super.walk(tree);

-            if ("{".equals(head))
-                return nonTerminal("braced"+(anon++),
+            if ("{".equals(head)) {
+                String s = "braced"+(anon++);
+                Union u = nonTerminal(s);
+                Union u2 = ((PreSequence)walk(tree, 0)).sparse(ws).buildUnion();
+                u2.add(Sequence.singleton(new Element[] { u }, 0, null, null));
+                return nonTerminal(s,

                                    new PreSequence[][] {
                                        new PreSequence[] {
                                            new PreSequence(new Element[] { CharToken.leftBrace,
                                    new PreSequence[][] {
                                        new PreSequence[] {
                                            new PreSequence(new Element[] { CharToken.leftBrace,

-                                                                           ((PreSequence)walk(tree, 0)).buildUnion(),
+                                                                           ws,
+                                                                           u2,
+                                                                           ws,

                                                                            CharToken.rightBrace
                                            })
                                        }
                                    },
                                    false,
                                    false);
                                                                            CharToken.rightBrace
                                            })
                                        }
                                    },
                                    false,
                                    false);

+            }

             return super.walk(tree);
         }
     }
             return super.walk(tree);
         }
     }