package edu.berkeley.sbp;
import edu.berkeley.sbp.util.*;
import edu.berkeley.sbp.*;
import edu.berkeley.sbp.*;
import java.io.*;
import java.util.*;
import java.lang.reflect.*;
import java.lang.ref.*;
/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */
public abstract class Sequence extends Element implements Iterable {
protected final Element[] elements;
final HashSet hated = new HashSet();
final HashSet needs = new HashSet();
final HashSet hates = new HashSet();
final Position firstp;
Atom follow = null;
// Static Constructors //////////////////////////////////////////////////////////////////////////////
abstract Sequence _clone();
Sequence dup() {
Sequence ret = _clone();
for(Sequence s : needs) { ret.needs.add(s); }
for(Sequence s : hates) { ret.hates.add(s); s.hated.add(ret); }
ret.follow = follow;
return ret;
}
/** create an empty sequence (matches the empty string) */
public static Sequence create() { return new Sequence.Constant.Empty(); }
/** create a sequence of one element */
public static Sequence create(Element e) { return create(new Element[] { e }, 0); }
/** 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); }
/** create a sequence which always evaluates to a constant result */
public static Sequence create(Element[] e, Object result) { return new Constant(e, result); }
/**
* create a sequence (general form)
* @param head the head of the output tree
* @param e the elements to match
* @param drop only elements of e whose corresponding boolean in drops
* is false 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 create(Object head, Element[] e, boolean[] drop, boolean foster) {
return foster
? new Unwrap(e, head, drop)
: new RewritingSequence(head, e, drop);
}
////////////////////////////////////////////////////////////////////////////////
/** return a new sequence identical to this one, but with a positive conjunct s */
public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
/** return a new sequence identical to this one, but with a negative conjunct s */
public Sequence not(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); return ret; }
/** return a new sequence identical to this one, but with a follow-set restricted to a */
public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
Iterable needs() { return needs; }
Iterable hates() { return hates; }
Position firstp() { return firstp; }
public Iterator iterator() { return new ArrayIterator(elements); }
protected Sequence(Element[] elements) {
this.elements = elements;
this.firstp = new Position(0);
}
// DO NOT MESS WITH THE FOLLOWING LINE!!!
private Forest.Many epsilonForm = null;
Forest epsilonForm() {
if (epsilonForm!=null) return epsilonForm;
epsilonForm = new Forest.Many();
epsilonForm.merge(firstp().rewrite(null, false));
return epsilonForm;
}
protected abstract Forest postReduce(Input.Region loc, Forest[] args, Position p);
// Position //////////////////////////////////////////////////////////////////////////////
/** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
class Position implements IntegerMappable {
private Forest zero = null;
public Forest zero() {
if (zero != null) return zero;
if (pos > 0) throw new Error();
return zero = rewrite(null);
}
final int pos;
private final Position next;
final Forest[] holder;
private Position(int pos) {
this.pos = pos;
this.next = pos==elements.length ? null : new Position(pos+1);
this.holder = new Forest[elements.length];
}
boolean isFirst() { return pos==0; }
/** the element immediately after this Position, or null if this is the last Position */
public Element element() { return pos>=elements.length ? null : elements[pos]; }
/** the element which produces the sequence to which this Position belongs */
public Sequence owner() { return Sequence.this; }
/** the next Position (the Position after this.element()) */
public Position next() { return next; }
/** true iff this Position is the last one in the sequence */
public boolean isLast() { return next()==null; }
// Position /////////////////////////////////////////////////////////////////////////////////
final Forest rewrite(Input.Region loc) { return rewrite(loc, true); }
private final Forest rewrite(Input.Region loc, boolean epsilonCheck) {
if (epsilonCheck && this==firstp()) return epsilonForm();
for(int i=0; i ret = Sequence.this.postReduce(loc, holder, this);
//for(int k=0; k");
return ret.toString();
}
private final int idx = master_position_idx++;
public int toInt() { return idx; }
}
private static int master_position_idx = 0;
// toString //////////////////////////////////////////////////////////////////////////////
public String toString() { return toString(new StringBuffer(), false).toString(); }
StringBuffer toString(StringBuffer sb) { return toString(sb, true); }
StringBuffer toString(StringBuffer sb, boolean spacing) {
for(int i=0; i ");
sb.append(follow);
}
return sb;
}
// Specialized Subclasses //////////////////////////////////////////////////////////////////////////////
static class Constant extends Sequence {
private final Object result;
public Constant(Element[] e, Object result) { super(e); this.result = result; }
Sequence _clone() { return new Constant(elements, result); }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
return (Forest)Forest.create(loc, result, null, false);
}
static class Drop extends Constant {
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[] { }); } }
}
static class Singleton extends Sequence {
private final int idx;
public Singleton(Element e) { this(new Element[] { e }, 0); }
public Singleton(Element[] e, int idx) { super(e); this.idx = idx; }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) { return args[idx]; }
Sequence _clone() { return new Singleton(elements,idx); }
}
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, tag, drops); }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
for(int i=0; i[] args2 = new Forest[count];
int j = 0;
for(int i=0; i tagf;
public RegionRewritingSequence(Functor tagfunctor, Element[] e, boolean[] drops) {
super(null, e, drops);
this.tagf = tagfunctor;
}
public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
this.tag = tagf.invoke(loc);
Forest ret = super.postReduce(loc, args, p);
this.tag = null;
return ret;
}
}
static class RewritingSequence extends Sequence {
/*private*/public /*final*/ Object tag;
private final boolean[] drops;
private int count = 0;
Sequence _clone() { return new RewritingSequence(tag, elements, drops); }
public RewritingSequence(Object tag, Element[] e) { this(tag, e, null); }
public RewritingSequence(Object tag, Element[] e, boolean[] drops) {
super(e);
this.tag = tag;
this.drops = drops == null ? new boolean[e.length] : drops;
for(int i=0; i Forest postReduce(Input.Region loc, Forest[] args, Position p) {
Forest[] args2 = new Forest[count];
int j = 0;
for(int i=0; i