Method gc

src/main/java/wycc/util/AbstractHeap.java:194–215

Force a garbage collection event. This removes all items which are unreachable from the root, and compacts those remaining down. @return

()

	 * @return
	 */
	@Override
	public boolean gc() {
		// Mark all reachable items
		BitSet reachable = findReachable(getRootItem(), new BitSet());
		// Sweep all unreachable items away
		int count = 0;
		for(int i=0;i!=syntacticItems.size();++i) {
			if(reachable.get(i)) {
				Item item = syntacticItems.get(i);
				// Reset the index of this item
				item.allocate(this, count);
				// Move the item down
				syntacticItems.set(count++, item);
			}
		}
		// Remove all unreachable items.
		for (int i = syntacticItems.size(); i > count; i = i - 1) {
			syntacticItems.remove(i - 1);
		}
		// Indicate whether anything changed
		return count < syntacticItems.size();
	}

	public void print(PrintWriter out) {
		String lenStr = Integer.toString(syntacticItems.size());