import java.lang.reflect.*;
/**
+ * <font color=blue>
* An efficient representation of a collection of trees (Tomita's
* shared packed parse forest).
+ * </font>
*/
public abstract class Forest<T> implements GraphViz.ToGraphViz {
/** expand this forest into a set of trees */
public void expand(HashSet<Tree<T>> ht) { expand(ht, new HashSet<Forest<T>>(), null); }
- /** create a new forest */
- public static <T> Forest<T> create(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
- return new One<T>(loc, head, children, unwrap);
+ static <T> Forest<T> create(Input.Region loc, T head, Forest<T>[] children, boolean lift) {
+ return new One<T>(loc, head, children, lift);
}
+ /** create a new forest */
+ public static <T> Forest<T> create(Input.Region loc, T head, Forest<T>[] children) {
+ return Forest.create(loc, head, children, false); }
+
// Package-Private //////////////////////////////////////////////////////////////////////////////
abstract void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus);
abstract void gather(HashSet<Forest<T>> ignore);
+ abstract void edges(GraphViz.Node n);
boolean ambiguous() { return false; }
- public abstract void edges(GraphViz.Node n);
-
// One //////////////////////////////////////////////////////////////////////////////
private final Forest<T>[] children;
/** if true, the last child's children are considered children of this node */
- private final boolean unwrap;
+ private final boolean lift;
- private One(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
+ private One(Input.Region loc, T head, Forest<T>[] children, boolean lift) {
this.location = loc;
this.head = head;
this.children = children==null ? emptyForestArray : new Forest[children.length];
if (children != null) System.arraycopy(children, 0, this.children, 0, children.length);
if (children != null) for(int i=0; i<children.length; i++) if (children[i]==null) throw new Error(i+"");
- this.unwrap = unwrap;
+ this.lift = lift;
}
public Tree<T> expand1() throws Ambiguous {
Tree<T>[] ret = new Tree[children.length];
for(int i=0; i<children.length; i++) ret[i] = children[i].expand1();
- return new Tree<T>(location, head, ret, unwrap);
+ return new Tree<T>(location, head, ret, lift);
}
void gather(HashSet<Forest<T>> hf) {
}
private void expand(final int i, Tree<T>[] ta, HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
if (i==children.length) {
- ht.add(new Tree<T>(location, head, ta, unwrap));
+ ht.add(new Tree<T>(location, head, ta, lift));
} else {
HashSet<Tree<T>> ht2 = new HashSet<Tree<T>>();
children[i].expand(ht2, ignore, bogus);
if (edges) return;
edges = true;
for(int i=0; i<children.length; i++) {
- if (i==children.length-1 && unwrap && !children[i].ambiguous()) {
+ if (i==children.length-1 && lift && !children[i].ambiguous()) {
children[i].edges(n);
} else {
n.edge(children[i], null);