final HashSet<Sequence> needs = new HashSet<Sequence>();
final HashSet<Sequence> hates = new HashSet<Sequence>();
- // FIXME: these are ugly -- migrate into Cache
+ // FIXME: these are ugly -- migrate into Grammar
HashMap<Sequence,Boolean> canNeed = new HashMap<Sequence,Boolean>();
HashMap<Sequence,Boolean> canKill = new HashMap<Sequence,Boolean>();
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); }
+ 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); }
+ public static Sequence create(Object result, Element[] e) {
+ return new RewritingSequence(result, e, trues(e.length)); }
+
+ private static boolean[] trues(int length) {
+ boolean[] ret = new boolean[length];
+ for(int i=0; i<ret.length; i++) ret[i] = true;
+ return ret;
+ }
/**
* create a sequence (general form)
* @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
+ * @param lifts which (if any) child trees to lift
**/
- 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 static Sequence create(Object head, Element[] e, boolean[] drop) {
+ return create(head, e, drop, new boolean[e.length]); }
+ public static Sequence create(Object head, Element[] e, boolean[] drop, boolean[] lifts) {
+ if (lifts==null) lifts = new boolean[e.length];
+ return new RewritingSequence(head, e, drop, lifts);
}
/** return a new sequence identical to this one, but with a positive conjunct <tt>s</tt> */
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!!!
- private Forest.Many epsilonForm = null;
- Forest epsilonForm(Input.Region loc) {
- if (epsilonForm!=null) return epsilonForm;
- epsilonForm = new Forest.Many();
- epsilonForm.merge(firstp().rewrite(loc, false));
- return epsilonForm;
- }
+ abstract Forest epsilonForm(Input.Region loc, Grammar cache);
protected abstract <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p);
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;
}
// Position /////////////////////////////////////////////////////////////////////////////////
- final <T> Forest<T> rewrite(Input.Region loc) { return rewrite(loc, true); }
- private final <T> Forest<T> rewrite(Input.Region loc, boolean epsilonCheck) {
- if (epsilonCheck && this==firstp()) return epsilonForm(loc);
+ final <T> Forest<T> rewrite(Input.Region loc, Grammar cache) {
+ if (this==firstp()) epsilonForm(loc, cache);
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(loc);
- if (holder[i]==null) throw new Error("bad " + i);
+ if (holder[i]==null) holder[i] = ((Union)elements[i]).epsilonForm(loc, cache);
+ if (holder[i]==null) throw new Error("bad");
}
- 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() {
public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
return (Forest<T>)Forest.create(loc, result, null, false);
}
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, result, null, false);
+ }
}
static class Singleton extends Sequence {
public Singleton(Element[] e, int idx) { super(e); this.idx = idx; }
public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] 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) { 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) {
- 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);
- 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, (T)tag, args2, true);
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return ((Union)elements[idx]).epsilonForm(loc, cache);
}
}
static class RewritingSequence extends Sequence {
private Object tag;
private final boolean[] drops;
- private int count = 0;
+ private final boolean[] lifts;
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) {
+ public RewritingSequence(Object tag, Element[] e, boolean[] drops) { this(tag, e, drops, new boolean[e.length]); }
+ public RewritingSequence(Object tag, Element[] e, boolean[] drops, boolean[] lifts) {
super(e);
if (tag==null) throw new Error();
this.tag = tag;
this.drops = drops == null ? new boolean[e.length] : drops;
+ int count = 0;
for(int i=0; i<this.drops.length; i++) if (!this.drops[i]) count++;
+ this.lifts = new boolean[count];
+ int j = 0;
+ for(int i=0; i<this.drops.length; i++)
+ if (!this.drops[i])
+ this.lifts[j++] = lifts[i];
}
public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
- Forest<T>[] args2 = new Forest[count];
+ Forest<T>[] args2 = new Forest[lifts.length];
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);
+ return Forest.create(loc, (T)tag, args2, lifts);
}
public StringBuffer toString(StringBuffer sb, boolean spacing) {
int len = sb.length();
if (spacing) for(int i=0; i<50-len; i++) sb.append(' ');
return sb;
}
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], lifts);
+ }
}
-
}
projects / sbp.git / blobdiff