*
* 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> {
}
}
- public static class Block /*implements Token*/ {
+ public static class Block {
Block parent;
public final int row;
public final int col;
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; }
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);
+ }
+ }
+
}