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;
}
- /** the empty sequence (matches the empty string) */
- public static final Sequence empty = new Sequence.Constant.Empty();
+ /** create an empty sequence (matches the empty string) */
+ public static Sequence create() { return 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); }
+ /** create a sequence of one element */
+ public static Sequence create(Element e) { return create(new Element[] { e }, 0); }
- /** after matching the sequence, insert a constant into the output tree */
- public static Sequence constant(Element[] e, Object o) { return new Constant(e, o); }
+ /** create a sequence which drops the result of all but one of its element */
+ public static Sequence create(Element[] e, int which) { return new Singleton(e, which); }
- /** after matching the sequence, place the result of the <tt>idx</tt>th match in the output tree */
- public static Sequence singleton(Element[] e, int idx) { return new Singleton(e, idx); }
- public static Sequence singleton(Element e) { return singleton(new Element[] { e }, 0); }
+ /** create a sequence which always evaluates to a constant result */
+ public static Sequence create(Element[] e, Object result) { return new Constant(e, result); }
/**
- * after matching the sequence, create the specified output tree
- * @param tag the tag for the output tree
- * @param e the elements to match
- * @param drops only elements of <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt>
- * is <i>false</i> will be included in the output tree
+ * create a sequence (general form)
+ * @param head the head of the output tree
+ * @param e the elements to match
+ * @param drop only elements of <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt>
+ * is <i>false</i> will be included in the output tree
+ * @param foster if true, all children of the last child (ie
+ * grandchildren) are promoted to children of this
+ * node; this is very useful for matching repetitions
**/
- public static Sequence rewritingSequence(Object tag, Element[] e, boolean[] drops) {
- return new RewritingSequence(tag, e, drops); }
-
- public static Sequence regionRewritingSequence(Functor<Input.Region,Object> tagfunctor, Element[] e, boolean[] drops) {
- return new RegionRewritingSequence(tagfunctor, e, drops); }
+ public static Sequence create(Object head, Element[] e, boolean[] drop, boolean foster) {
+ return foster
+ ? new Unwrap(e, head, drop)
+ : new RewritingSequence(head, e, drop);
+ }
////////////////////////////////////////////////////////////////////////////////
- public Element follow = null;
- public final Topology follow() { return follow==null ? null : Atom.toAtom(follow); }
+ /** return a new sequence identical to this one, but with a positive conjunct <tt>s</tt> */
+ public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
- 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; }
+ /** return a new sequence identical to this one, but with a negative conjunct <tt>s</tt> */
public Sequence not(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); return ret; }
- protected final Element[] elements;
+ /** return a new sequence identical to this one, but with a follow-set restricted to <tt>a</tt> */
+ public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
- 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;
+ Iterable<Sequence> needs() { return needs; }
+ Iterable<Sequence> hates() { return hates; }
- final Position firstp;
Position firstp() { return firstp; }
public Iterator<Element> iterator() { return new ArrayIterator<Element>(elements); }
}
// DO NOT MESS WITH THE FOLLOWING LINE!!!
- private Forest.Ref epsilonForm = null;
+ private Forest.Many epsilonForm = null;
Forest epsilonForm() {
if (epsilonForm!=null) return epsilonForm;
- epsilonForm = new Forest.Ref();
+ epsilonForm = new Forest.Many();
epsilonForm.merge(firstp().rewrite(null, false));
return epsilonForm;
}
// 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 {
Sequence _clone() { return new Singleton(elements,idx); }
}
- public static Unwrap unwrap(Element[] e, Object tag, boolean[] drops) { return new Unwrap(e, tag, drops); }
static class Unwrap extends Sequence {
private boolean[] drops;
private final Object tag;
public Unwrap(Element[] e, Object tag) { super(e); this.drops = null; this.tag = tag; }
public Unwrap(Element[] e, Object tag, boolean[] drops) { super(e); this.drops = drops; this.tag = tag; }
- Sequence _clone() { return new Unwrap(elements, drops); }
+ Sequence _clone() { return new Unwrap(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, true);
}
}
- // Repeat //////////////////////////////////////////////////////////////////////////////
-
- /** repeat zero or one times */
- public static Element maybe(Element e) { return new Repeat(e, true, false, null, null); }
- public static Element maybe(Element e, Object tag) { return new Repeat(e, true, false, null, tag); }
- /** repeat zero or more times */
- public static Element many0(Element e) { return new Repeat(e, true, true, null, null); }
- public static Element many0(Element e, Object tag) { return new Repeat(e, true, true, null, tag); }
- /** repeat zero or more times, separated by <tt>sep</tt> */
- public static Element many0(Element e, Element sep) { return new Repeat(e, true, true, sep, null); }
- public static Element many0(Element e, Element sep, Object tag) { return new Repeat(e, true, true, sep, tag); }
- /** repeat one or more times */
- public static Element many1(Element e) { return new Repeat(e, false, true, null, null); }
- public static Element many1(Element e, Object tag) { return new Repeat(e, false, true, null, tag); }
- /** repeat one or more times, separated by <tt>sep</tt> */
- public static Element many1(Element e, Element sep) { return new Repeat(e, false, true, sep, null); }
- public static Element many1(Element e, Element sep, Object tag) { return new Repeat(e, false, true, sep, tag); }
-
- /** repeat zero or more times, matching a maximal sequence of atoms */
- public static Element maximal0(Atom e) { return new Repeat.Maximal(e, true, true, null); }
- public static Element maximal0(Atom e, Object tag) { return new Repeat.Maximal(e, true, true, tag); }
- /** repeat one or more times, matching a maximal sequence of atoms */
- public static Element maximal1(Atom e) { return new Repeat.Maximal(e, false, true, null); }
- public static Element maximal1(Atom e, Object tag) { return new Repeat.Maximal(e, false, true, tag); }
- /** repeat one or more times, separated by an atom <tt>sep</tt>, matching a maximal sequence */
- public static Element maximal1(Element e, Atom sep) { return new Repeat.Maximal(e, false, true, sep, null); }
- public static Element maximal1(Element e, Atom sep, Object tag) { return new Repeat.Maximal(e, false, true, sep, tag); }
-
- public static Element repeatMaximal(Atom e, boolean zero, boolean many, Object tag) {
- return new Repeat.Maximal(e, zero, many, tag); }
- public static Element repeatMaximal(Element e, boolean zero, boolean many, Atom sep, Object tag) {
- return new Repeat.Maximal(e, zero, many, sep, tag); }
- public static Element repeat(Element e, boolean zero, boolean many, Object tag) {
- return new Repeat(e, zero, many, tag); }
- public static Element repeat(Element e, boolean zero, boolean many, Element sep, Object tag) {
- return new Repeat(e, zero, many, sep, tag); }
}
projects / sbp.git / blobdiff