+ else if ("ps2".equals(head)) {
+ Object[] o1 = (Object[])walk(tree, 0);
+ String s = string(tree.child(1));
+ Object[] o2 = (Object[])walk(tree, 2);
+ if (o1==null) o1 = new Object[0];
+ if (o2==null) o2 = new Object[0];
+ Object[] o3 = new Object[o1.length + o2.length + 1];
+ System.arraycopy(o1, 0, o3, 0, o1.length);
+ o3[o1.length] = string(s);
+ System.arraycopy(o2, 0, o3, o1.length+1, o2.length);
+ PreSequence ret = new PreSequence(o3, s);
+ ret.drops[o1.length] = o3.length>1;
+ return ret;
+ } else if ("[".equals(head) || "[~".equals(head)) {