hoisted getLocation() out of Token and into Token.Stream

[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 915158b..8ee70ca 100644 (file)
--- a/src/edu/berkeley/sbp/tib/Tib.java
+++ b/src/edu/berkeley/sbp/tib/Tib.java
@@ -21,9 +21,7 @@ import java.io.*;
  *
  *   This was written as an ad-hoc parser to facilitate
  *   experimentation with the TIB spec.  Once the spec is finalized it
- *   should probably be rewritten using a parser-generator, if
- *   possible (it is unclear whether or not the associated grammar is
- *   context-free).
+ *   should probably be rewritten.
  */
 public class Tib implements Token.Stream<CharToken> {
 
@@ -42,6 +40,7 @@ public class Tib implements Token.Stream<CharToken> {
 
     int _row = 0;
     int _col = 0;
+    public Token.Location getLocation() { return new CharToken.CartesianLocation(_row, _col); }
     public CharToken next() throws IOException {
         if (cur==null) return null;
         if (s != null) {
@@ -49,7 +48,7 @@ public class Tib implements Token.Stream<CharToken> {
                 char c = s.charAt(spos++);
                 if (c=='\n') { _row++; _col = 0; }
                 else _col++;
-                return new CharToken(c, _row, _col);
+                return new CharToken(c);
             }
             s = null;
         }
@@ -57,7 +56,7 @@ public class Tib implements Token.Stream<CharToken> {
             pos = cur.iip+1;
             cur = cur.parent;
             if (cur==null) return null;
-            return CharToken.right(_row, _col);
+            return CharToken.right;
         }
         Object o = cur.child(pos++);
         if (o instanceof String) {
@@ -77,7 +76,7 @@ public class Tib implements Token.Stream<CharToken> {
         }
         cur = (Block)o;
         pos = 0;
-        return CharToken.left(_row, _col);
+        return CharToken.left;
     }
 
     public static Block parse(BufferedReader br) throws Invalid, IOException {
@@ -129,7 +128,7 @@ public class Tib implements Token.Stream<CharToken> {
         }
     }
 
-    public static class Block /*implements Token*/ {
+    public static class Block {
                       Block  parent;
         public  final int    row;
         public  final int    col;
@@ -137,7 +136,6 @@ public class Tib implements Token.Stream<CharToken> {
         private final Vector children = new Vector();
         private       String pending  = "";
 
-        //public Location getLocation() { return /*new Location.Cartesian(row, col)*/null; }
         public int    size() { return children.size(); }
         public Object child(int i) { return children.elementAt(i); }
         public boolean isLiteral() {  return false; }
@@ -288,5 +286,37 @@ public class Tib implements Token.Stream<CharToken> {
         return ret.toString();
     }
 
+    // Grammar //////////////////////////////////////////////////////////////////////////////
+
+    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);
+            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,
+                                                                           ws,
+                                                                           u2,
+                                                                           ws,
+                                                                           CharToken.rightBrace
+                                           })
+                                       }
+                                   },
+                                   false,
+                                   false);
+            }
+            return super.walk(tree);
+        }
+    }
+
 }