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 createLeft(Object head, Element[] e, boolean[] drop, boolean foster) {
- return foster
- ? new UnwrapLeft(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> */
}
}
- 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 Forest.create(loc, tag, new Forest[0], false);
- }
- }
-
- static class UnwrapLeft extends Sequence {
- private boolean[] drops;
- private final Object tag;
- public UnwrapLeft(Element[] e, Object tag) { this(e, tag, null); }
- public UnwrapLeft(Element[] e, Object tag, boolean[] drops) { super(e); this.drops = drops; this.tag = tag; }
- Sequence _clone() { return new UnwrapLeft(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, false, 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, false, true);
- }
- Forest epsilonForm(Input.Region loc, Grammar cache) {
- return Forest.create(loc, tag, new Forest[0], false);
- }
- }
-
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];
- 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();
return sb;
}
Forest epsilonForm(Input.Region loc, Grammar cache) {
- return Forest.create(loc, tag, new Forest[0], false);
+ return Forest.create(loc, tag, new Forest[0], lifts);
}
}
-
}
projects / sbp.git / blobdiff