// Static Constructors //////////////////////////////////////////////////////////////////////////////
+ public abstract Sequence and(Sequence s);
+ public abstract Sequence not(Sequence s);
+
+ private void needs(Sequence s) { s.needed.add(this); needs.add(s); }
+ private void hates(Sequence s) { s.hated.add(this); hates.add(s); }
+
/** the empty sequence (matches the empty string) */
public static final Sequence empty = new Sequence.Constant.Empty();
////////////////////////////////////////////////////////////////////////////////
public Element noFollow = null;
+ public String name = null;
+ public void setName(String name) { this.name = name; }
public final Topology noFollow() { return noFollow==null ? null : noFollow.toAtom(); }
Topology toAtom() {
protected final Element[] elements;
+ HashSet<Sequence> needed;
+ HashSet<Sequence> hated;
final HashSet<Sequence> needs;
final HashSet<Sequence> hates;
- boolean lame = false;
+ public boolean lame = false;
final Position firstp;
Position firstp() { return firstp; }
protected Sequence(Element[] elements, HashSet<Sequence> and, HashSet<Sequence> not) {
this.needs = and==null ? new HashSet<Sequence>() : and;
this.hates = not==null ? new HashSet<Sequence>() : not;
+ if (this.needs != null)
+ for(Sequence s : this.needs)
+ (s.needed==null?(s.needed=new HashSet<Sequence>()):s.needed).add(this);
+ if (this.hates != null)
+ for(Sequence s : this.hates)
+ (s.hated==null?(s.hated=new HashSet<Sequence>()):s.hated).add(this);
this.elements = elements;
this.firstp = new Position(0);
}
Forest epsilonForm() {
if (epsilonForm==null) {
epsilonForm = new Forest.Ref();
- Forest fo = firstp().rewrite(null);
- epsilonForm.merge(fo);
+ epsilonForm.merge(firstp().rewrite2(null));
}
return epsilonForm;
}
- protected abstract <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args);
+ protected abstract <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args);
// Position //////////////////////////////////////////////////////////////////////////////
/** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
- public class Position {
+ public 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;
}
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]; }
/** true iff this Position is the last one in the sequence */
public boolean isLast() { return next()==null; }
- // Reduction /////////////////////////////////////////////////////////////////////////////////
+ // Position /////////////////////////////////////////////////////////////////////////////////
+
+ final <T> Forest<T> rewrite(Input.Location loc) {
+ if (this==firstp()) return epsilonForm();
+ return rewrite2(loc);
+ }
- final <T> Forest<T> rewrite(Token.Location loc) {
- if (this==firstp() && eps) return epsilonForm;
- eps = true;
- for(int i=pos; i<elements.length; i++) if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+ final <T> Forest<T> rewrite2(Input.Location loc) {
+ for(int i=0; i<pos; i++) if (holder[i]==null) throw new Error("realbad " + i);
+ for(int i=pos; i<elements.length; i++) {
+ if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+ if (holder[i]==null) throw new Error("bad " + i);
+ }
Forest<T> ret = Sequence.this.postReduce(loc, holder);
for(int k=0; k<pos; k++) holder[k] = null; // to help GC
- if (this==firstp()) { if (epsilonForm==null) epsilonForm=new Forest.Ref(); epsilonForm.merge(ret); return epsilonForm; }
return ret;
}
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 //////////////////////////////////////////////////////////////////////////////
static class Constant extends Sequence {
private final Object result;
public Constant(Element[] e, Object result, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.result = result; }
- public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) {
- return (Forest<T>)Forest.leaf(loc, result, this);
+ public Sequence and(Sequence s) { Sequence ret = new Constant(elements, result, needs, hates); ret.needs(s); return ret; }
+ public Sequence not(Sequence s) { Sequence ret = new Constant(elements, result, needs, hates); ret.hates(s); return ret; }
+ public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
+ return (Forest<T>)Forest.leaf(loc, result);
}
static class Drop extends Constant {
public Drop(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not, boolean lame) {
private final int idx;
public Singleton(Element e, HashSet<Sequence> and, HashSet<Sequence> not) { this(new Element[] { e }, 0, and, not); }
public Singleton(Element[] e, int idx, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.idx = idx; }
- public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) { return (Forest<T>)Forest.singleton(loc, args[idx], this); }
+ public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) { return (Forest<T>)Forest.singleton(loc, args[idx]); }
+ public Sequence and(Sequence s) { Sequence ret = new Singleton(elements, idx, needs, hates); ret.needs(s); return ret; }
+ public Sequence not(Sequence s) { Sequence ret = new Singleton(elements, idx, needs, hates); ret.hates(s); return ret; }
}
- static class Unwrap extends Sequence {
+ public static class Unwrap extends Sequence {
private boolean[] drops;
public Unwrap(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.drops = null; }
public Unwrap(Element[] e, boolean[] drops, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.drops = drops; }
- public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) {
- if (drops==null) return Forest.create(loc, null, args, this, true, false);
+ public Sequence and(Sequence s) { Sequence ret = new Unwrap(elements, drops, needs, hates); ret.needs(s); return ret; }
+ public Sequence not(Sequence s) { Sequence ret = new Unwrap(elements, drops, needs, hates); ret.hates(s); return ret; }
+ public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
+ for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
+ if (drops==null) return Forest.create(loc, null, args, true, false);
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, null, args2, this, true, false);
+ return Forest.create(loc, null, args2, true, false);
}
}
static class RewritingSequence extends Sequence {
- private final Object tag;
+ /*private*/public final Object tag;
private final boolean[] drops;
private int count = 0;
+ public Sequence and(Sequence s) { Sequence ret = new RewritingSequence(tag, elements, drops, needs, hates); ret.needs(s); return ret; }
+ public Sequence not(Sequence s) { Sequence ret = new RewritingSequence(tag, elements, drops, needs, hates); ret.hates(s); return ret; }
public RewritingSequence(Object tag, Element[] e, HashSet<Sequence> and, HashSet<Sequence> not) { this(tag, e, null, and, not); }
public RewritingSequence(Object tag, Element[] e, boolean[] drops, HashSet<Sequence> and, HashSet<Sequence> not) {
super(e, and, not);
this.drops = drops == null ? new boolean[e.length] : drops;
for(int i=0; i<this.drops.length; i++) if (!this.drops[i]) count++;
}
- public <T> Forest<T> postReduce(Token.Location loc, Forest<T>[] args) {
+ public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
Forest<T>[] args2 = new Forest[count];
int j = 0;
for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
//System.out.println("reduce \""+tag+"\"");
- return Forest.create(loc, (T)tag, args2, this, false, false);
+ return Forest.create(loc, (T)tag, args2, false, false);
}
public StringBuffer toString(StringBuffer sb, boolean spacing) {
int len = sb.length();
projects / sbp.git / blobdiff