X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=f4315182d654770e32ee45c8cc9017a3d17dda1e;hp=d25260450ef90d7ae0ad6466d69edc00026ff283;hb=75d0fa39d405292f4b831a6d1743f2aeea01ebd4;hpb=0516ea34996c86664928ef948013b749876b87ec
diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index d252604..f431518 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -7,78 +7,106 @@ import java.util.*;
import java.lang.reflect.*;
import java.lang.ref.*;
-/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */
+/** 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 //////////////////////////////////////////////////////////////////////////////
- /** the empty sequence (matches the empty string) */
- public static final Sequence empty = new Sequence.Constant.Empty();
+ 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(); }
- /** after matching the sequence, do not add anything to the output tree */
- public static Sequence drop(Element[] e, HashSet and, HashSet not, boolean lame) { return new Constant.Drop(e, and, not, 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, HashSet and, HashSet not) { return new Constant(e, o, and, not); }
+ /** 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 idxth match in the output tree */
- public static Sequence singleton(Element[] e, int idx, HashSet and, HashSet not) { return new Singleton(e, idx, and, not); }
+ /** 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 e whose corresponding boolean in drops is false 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 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 rewritingSequence(Object tag, Element[] e, boolean[] drops, HashSet and, HashSet not) {
- return new RewritingSequence(tag, e, drops, and, not); }
+ 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 Topology noFollow() { return null; }
+ /** 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; }
- Topology toAtom() {
- if (elements.length!=1) throw new RuntimeException("cannot invoke toAtom() on a Sequence with " + elements.length + " elements: " + this);
- return elements[0].toAtom();
- }
+ /** 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; }
- protected final Element[] elements;
+ /** 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; }
- final HashSet needs;
- final HashSet hates;
- boolean lame = false;
+ Iterable needs() { return needs; }
+ Iterable hates() { return hates; }
- final Position firstp;
Position firstp() { return firstp; }
public Iterator iterator() { return new ArrayIterator(elements); }
- protected Sequence(Element[] elements, HashSet and, HashSet not) {
- this.needs = and==null ? new HashSet() : and;
- this.hates = not==null ? new HashSet() : not;
- //for(Sequence s : needs) s.lame = true;
- //for(Sequence s : hates) s.lame = true;
+ protected Sequence(Element[] elements) {
this.elements = elements;
this.firstp = new Position(0);
}
- void reachable(HashSet h) { firstp().reachable(h); }
-
- Forest epsilonForm() { return firstp().rewrite(null); }
+ // 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(Token.Location loc, Forest[] args);
+ 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" */
- public class Position {
+ class Position implements IntegerMappable {
- void reachable(HashSet h) {
- if (h.contains(this)) return;
- h.add(this);
- if (element() != null) element().reachable(h);
+ 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;
@@ -90,11 +118,6 @@ public abstract class Sequence extends Element implements Iterable {
}
boolean isFirst() { return pos==0; }
- boolean isRightNullable(Walk.Cache cache) {
- if (isLast()) return true;
- if (!element().possiblyEpsilon(cache)) return false;
- return next().isRightNullable(cache);
- }
/** the element immediately after this Position, or null if this is the last Position */
public Element element() { return pos>=elements.length ? null : elements[pos]; }
@@ -108,12 +131,18 @@ public abstract class Sequence extends Element implements Iterable {
/** true iff this Position is the last one in the sequence */
public boolean isLast() { return next()==null; }
- // Reduction /////////////////////////////////////////////////////////////////////////////////
+ // Position /////////////////////////////////////////////////////////////////////////////////
- Forest rewrite(Token.Location loc) {
- for(int i=pos; i ret = Sequence.this.postReduce(loc, holder);
- for(int k=0; k 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 {
for(Position p = Sequence.this.firstp(); p != null; p = p.next()) {
ret.append(' ');
if (p==this) ret.append(" | ");
- if (p.element()!=null) ret.append(p.element().possiblyEpsilon(null) ? "["+p.element()+"]" : p.element());
+ if (p.element()!=null) ret.append(p.element());
else ret.append(' ');
}
ret.append("}>");
return ret.toString();
}
+ private final int idx = master_position_idx++;
+ public int toInt() { return idx; }
}
-
+ private static int master_position_idx = 0;
// toString //////////////////////////////////////////////////////////////////////////////
@@ -141,6 +172,10 @@ public abstract class Sequence extends Element implements Iterable {
sb.append(elements[i].toString());
sb.append(' ');
}
+ if (follow != null) {
+ sb.append("-> ");
+ sb.append(follow);
+ }
return sb;
}
@@ -149,66 +184,90 @@ public abstract class Sequence extends Element implements Iterable {
static class Constant extends Sequence {
private final Object result;
- public Constant(Element[] e, Object result, HashSet and, HashSet not) { super(e, and, not); this.result = result; }
- public Forest postReduce(Token.Location loc, Forest[] args) {
- return (Forest)Forest.leaf(loc, result, this);
+ 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 {
- public Drop(Element[] e, HashSet and, HashSet not, boolean lame) {
- super(e, null, and, not);
- this.lame = lame;
- }
+ Sequence _clone() { return new Drop(elements); }
+ public Drop(Element[] e) { super(e, null); }
}
- static class Empty extends Sequence.Constant.Drop { public Empty() { super(new Element[] { }, null, null, false); } }
+ 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, HashSet and, HashSet not) { this(new Element[] { e }, 0, and, not); }
- public Singleton(Element[] e, int idx, HashSet and, HashSet not) { super(e, and, not); this.idx = idx; }
- public Forest postReduce(Token.Location loc, Forest[] args) { return (Forest)Forest.singleton(loc, args[idx], this); }
+ 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;
- public Unwrap(Element[] e, HashSet and, HashSet not) { super(e, and, not); this.drops = null; }
- public Unwrap(Element[] e, boolean[] drops, HashSet and, HashSet not) { super(e, and, not); this.drops = drops; }
- public Forest postReduce(Token.Location loc, Forest[] args) {
- if (drops==null) return Forest.create(loc, null, args, this, true, false);
+ 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 final Object tag;
+ /*private*/public /*final*/ Object tag;
private final boolean[] drops;
private int count = 0;
- public RewritingSequence(Object tag, Element[] e, HashSet and, HashSet not) { this(tag, e, null, and, not); }
- public RewritingSequence(Object tag, Element[] e, boolean[] drops, HashSet and, HashSet not) {
- super(e, and, not);
+ 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(Token.Location loc, Forest[] args) {
+ public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
Forest[] args2 = new Forest[count];
int j = 0;
for(int i=0; i ");
- sb.append(tag);
return sb;
}
}
+
}