protected final Element[] elements;
- public boolean needed_or_hated = false;
-
- public HashMap<Sequence,Boolean> canNeed = new HashMap<Sequence,Boolean>();
- public HashMap<Sequence,Boolean> canKill = new HashMap<Sequence,Boolean>();
-
- final HashSet<Sequence> hated = new HashSet<Sequence>();
+ boolean needed_or_hated = false;
+ boolean in_a_union = false;
final HashSet<Sequence> needs = new HashSet<Sequence>();
final HashSet<Sequence> hates = new HashSet<Sequence>();
+ // FIXME: these are ugly -- migrate into Cache
+ HashMap<Sequence,Boolean> canNeed = new HashMap<Sequence,Boolean>();
+ HashMap<Sequence,Boolean> canKill = new HashMap<Sequence,Boolean>();
+
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); }
: new RewritingSequence(head, e, drop);
}
- ////////////////////////////////////////////////////////////////////////////////
-
/** 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); s.needed_or_hated=true; return ret; }
+ public Sequence and(Sequence s) {
+ if (s.in_a_union)
+ throw new RuntimeException("you may not use a sequence as a conjunct if it belongs to a Union");
+ Sequence ret = dup();
+ ret.needs.add(s);
+ s.needed_or_hated=true;
+ return ret;
+ }
/** return a new sequence identical to this one, but with a negative conjunct <tt>s</tt> */
- public Sequence andnot(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); s.needed_or_hated=true; return ret; }
+ public Sequence andnot(Sequence s) {
+ if (s.in_a_union)
+ throw new RuntimeException("you may not use a sequence as a conjunct if it belongs to a Union");
+ Sequence ret = dup();
+ ret.hates.add(s);
+ s.needed_or_hated=true;
+ return ret;
+ }
/** 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; }
- boolean hatesAny(Iterable<Sequence> it) {
- if (hates.isEmpty()) return false;
- for(Sequence s : it) if (hates.contains(s)) return true;
- return false;
+ ////////////////////////////////////////////////////////////////////////////////
+
+ abstract Sequence _clone();
+ private Sequence dup() {
+ Sequence ret = _clone();
+ for(Sequence s : needs) { ret.needs.add(s); }
+ for(Sequence s : hates) { ret.hates.add(s); }
+ ret.follow = follow;
+ return ret;
}
Iterable<Sequence> needs() { return needs; }
Iterable<Sequence> hates() { return hates; }
Position firstp() { return firstp; }
+ Position lastp() { return firstp().last(); }
public Iterator<Element> iterator() { return new ArrayIterator<Element>(elements); }
protected Sequence(Element[] elements) {
this.elements = elements;
- this.firstp = new Position(0);
+ for(int i=0; i<elements.length; i++)
+ if (elements[i]==null)
+ throw new RuntimeException("cannot have nulls in a sequence: " + this);
+ this.firstp = new Position(0, null);
}
// DO NOT MESS WITH THE FOLLOWING LINE!!!
class Position implements IntegerMappable {
public int ord = -1;
- public int compareTo(Position p, Walk.Cache cache) {
- Position position = this;
- Position rposition = p;
- int ret = 0;
- if (Reduction.canKill(cache, position, rposition) &&
- Reduction.canKill(cache, rposition, position)) throw new Error();
- if (Reduction.canKill(cache, position, rposition)) ret = 1;
- else if (Reduction.canKill(cache, rposition, position)) ret = -1;
- if (Reduction.canNeed(cache, position, rposition)) ret = 1;
- else if (Reduction.canNeed(cache, rposition, position)) ret = -1;
- return ret;
- }
private Forest zero = null;
public Forest zero(Input.Region reg) {
if (zero != null) return zero;
- if (pos > 0) throw new Error();
+ if (pos > 0) throw new RuntimeException("Position.zero(): pos>0");
return zero = rewrite(reg);
}
-
final int pos;
private final Position next;
+ private final Position prev;
final Forest[] holder;
- private Position(int pos) {
+ private Position(int pos, Position prev) {
this.pos = pos;
- this.next = pos==elements.length ? null : new Position(pos+1);
+ this.next = pos==elements.length ? null : new Position(pos+1, this);
this.holder = new Forest[elements.length];
+ this.prev = prev;
}
boolean isFirst() { return pos==0; }
/** true iff this Position is the last one in the sequence */
public boolean isLast() { return next()==null; }
+ public Position last() { return isLast() ? this : next().last(); }
+ public Position prev() { return prev; }
// Position /////////////////////////////////////////////////////////////////////////////////
if (holder[i]==null) holder[i] = elements[i].epsilonForm(loc);
if (holder[i]==null) throw new Error("bad " + i);
}
- Forest<T> ret = Sequence.this.postReduce(loc, holder, this);
- //for(int k=0; k<pos; k++) holder[k] = null; // to help GC
- return ret;
+ return Sequence.this.postReduce(loc, holder, this);
}
public String toString() {
StringBuffer toString(StringBuffer sb) { return toString(sb, true); }
StringBuffer toString(StringBuffer sb, boolean spacing) {
for(int i=0; i<elements.length; i++) {
- sb.append(elements[i].toString());
+ sb.append(elements[i]+"");
sb.append(' ');
}
if (follow != null) {
static class Constant extends Sequence {
private final Object result;
- public Constant(Element[] e, Object result) { super(e); this.result = result; }
+ public Constant(Element[] e, Object result) {
+ super(e);
+ if (result==null) throw new Error("constant sequences may not have result==null");
+ this.result = result;
+ }
Sequence _clone() { return new Constant(elements, result); }
public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
return (Forest<T>)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 {
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) { this(e, tag, null); }
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 <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
}
}
-
-
- static class RegionRewritingSequence extends RewritingSequence {
- private Functor<Input.Region, Object> tagf;
- public RegionRewritingSequence(Functor<Input.Region,Object> tagfunctor, Element[] e, boolean[] drops) {
- super(null, e, drops);
- this.tagf = tagfunctor;
- }
- public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
- this.tag = tagf.invoke(loc);
- Forest<T> ret = super.postReduce(loc, args, p);
- this.tag = null;
- return ret;
- }
- }
-
static class RewritingSequence extends Sequence {
- /*private*/public /*final*/ Object tag;
+ private 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);
+ if (tag==null) throw new Error();
this.tag = tag;
this.drops = drops == null ? new boolean[e.length] : drops;
for(int i=0; i<this.drops.length; i++) if (!this.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];
- //System.out.println("reduce \""+tag+"\"");
return Forest.create(loc, (T)tag, args2, false);
}
public StringBuffer toString(StringBuffer sb, boolean spacing) {