import java.lang.reflect.*;
import java.lang.ref.*;
-/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */
+/** <font color=green>juxtaposition; zero or more adjacent Elements; can specify a rewriting</font> */
public abstract class Sequence extends Element implements Iterable<Element> {
+ protected final Element[] elements;
+
+ final HashSet<Sequence> hated = new HashSet<Sequence>();
+
+ final HashSet<Sequence> needs = new HashSet<Sequence>();
+ final HashSet<Sequence> hates = new HashSet<Sequence>();
+
+ final Position firstp;
+
+ Atom follow = null;
+
// Static Constructors //////////////////////////////////////////////////////////////////////////////
abstract Sequence _clone();
Sequence dup() {
Sequence ret = _clone();
- for(Sequence s : needs) { ret.needs.add(s); s.needed.add(ret); }
+ for(Sequence s : needs) { ret.needs.add(s); }
for(Sequence s : hates) { ret.hates.add(s); s.hated.add(ret); }
ret.follow = follow;
- ret.lame = lame;
return ret;
}
public static final Sequence empty = new Sequence.Constant.Empty();
/** after matching the sequence, do not add anything to the output tree */
- public static Sequence drop(Element[] e, boolean lame) { return new Constant.Drop(e, lame); }
+ public static Sequence drop(Element[] e) { return new Constant.Drop(e); }
/** after matching the sequence, insert a constant into the output tree */
public static Sequence constant(Element[] e, Object o) { return new Constant(e, o); }
////////////////////////////////////////////////////////////////////////////////
- public Element follow = null;
- public final Topology follow() { return follow==null ? null : Atom.toAtom(follow); }
-
- Topology toAtom() {
- if (elements.length!=1)
- throw new RuntimeException("cannot invoke toAtom() on a Sequence with " + elements.length + " elements: " + this);
- return Atom.toAtom(elements[0]);
- }
-
- public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); s.needed.add(ret); return ret; }
+ public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
public Sequence not(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); return ret; }
+ public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
- protected final Element[] elements;
-
- final HashSet<Sequence> needed = new HashSet<Sequence>();
- final HashSet<Sequence> hated = new HashSet<Sequence>();
- final HashSet<Sequence> needs = new HashSet<Sequence>();
- final HashSet<Sequence> hates = new HashSet<Sequence>();
- public boolean lame = false;
+ public Iterable<Sequence> needs() { return needs; }
+ public Iterable<Sequence> hates() { return hates; }
- final Position firstp;
Position firstp() { return firstp; }
public Iterator<Element> iterator() { return new ArrayIterator<Element>(elements); }
// Position //////////////////////////////////////////////////////////////////////////////
/** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
- public class Position implements IntegerMappable {
+ class Position implements IntegerMappable {
private Forest zero = null;
public Forest zero() {
return (Forest<T>)Forest.create(loc, result, null, false);
}
static class Drop extends Constant {
- Sequence _clone() { return new Drop(elements, lame); }
- public Drop(Element[] e, boolean lame) {
- super(e, null);
- this.lame = lame;
- }
+ Sequence _clone() { return new Drop(elements); }
+ public Drop(Element[] e) { super(e, null); }
}
static class Empty extends Sequence.Constant.Drop {
Sequence _clone() { return new Empty(); }
- public Empty() { super(new Element[] { }, false); } }
+ public Empty() { super(new Element[] { }); } }
}
static class Singleton extends Sequence {