+ public UnwrapLeft(Element[] e, Object tag) { this(e, tag, null); }
+ public UnwrapLeft(Element[] e, Object tag, boolean[] drops) { super(e); this.drops = drops; this.tag = tag; }
+ Sequence _clone() { return new UnwrapLeft(elements, tag, drops); }
+ public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
+ for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
+ if (drops==null) return Forest.create(loc, (T)tag, args, false, true);
+ int count = 0;
+ for(int i=0; i<drops.length; i++) if (!drops[i]) count++;
+ Forest<T>[] args2 = new Forest[count];
+ int j = 0;
+ for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
+ return Forest.create(loc, (T)tag, args2, false, true);
+ }
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], false);
+ }
+ }
+
+ static class RewritingSequence extends Sequence {
+ private Object tag;