import java.lang.reflect.*;
import java.lang.ref.*;
-/** an element which can produce one of several alternatives */
+/** <font color=green>an element which can produce one of several alternatives</font> */
public class Union extends Element implements Iterable<Sequence> {
private final String name;
private final boolean synthetic;
+
private final List<Sequence> alternatives = new ArrayList<Sequence>();
+ public Union(String name) { this(name, false); }
+
/**
* Since every cycle in a non-degenerate grammar contains at
* least one Union, every instance of this class must be able to
* display itself in both "long form" (list of the long forms of
- * its alternatives) and "short form" (some abbreviation).
+ * its alternatives) and "short form" (some name).
*
- * @param shortForm the "short form" display; usually
+ * @param shortForm the "short form" display; for display purposes only
* @param synthetic if true, this Union's "long form" is "obvious" and should not be displayed when printing the grammar
*/
- public Union() { this(null, false); }
- public Union(String name) { this(name, false); }
public Union(String name, boolean synthetic) {
this.name = name;
this.synthetic = synthetic;
}
- public Iterator<Sequence> iterator() { return alternatives.iterator(); }
public boolean contains(Sequence s) { return alternatives.contains(s); }
+ public Iterator<Sequence> iterator() { return alternatives.iterator(); }
/** adds an alternative */
public void add(Sequence s) {
+ if (alternatives.contains(s)) return;
alternatives.add(s);
-
- // FIXME: does this make sense?
- for(Sequence n : s.needs) add(n);
- for(Sequence n : s.hates) add(n);
}
+
// Epsilon Form //////////////////////////////////////////////////////////////////////////////
// FIXME
return epsilonForm;
}
+
// Display //////////////////////////////////////////////////////////////////////////////
public String getName() {
private void bodyToString(StringBuffer sb, String before, String between) {
boolean first = true;
for(Sequence s : this) {
- if (s.lame) continue;
// FIXME: what to do here about printing out negated sequences?
sb.append(first ? before : between);
first = false;