/** an element which can produce one of several alternatives */
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() { this(null, false); }
+ 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
* @param shortForm the "short form" display; usually
* @param synthetic if true, this Union's "long form" is "obvious" and should not be displayed when printing the grammar
*/
- public Union(String shortForm) { this(shortForm, false); }
- public Union(String shortForm, boolean synthetic) {
- this.shortForm = shortForm;
+ public Union(String name, boolean synthetic) {
+ this.name = name;
this.synthetic = synthetic;
}
- /** display form for the Union (ie not including the RHS) */
- final String shortForm;
-
- /** this is just a hint to use when printing out the grammar in visual form */
- final boolean synthetic;
-
- /** the actual alternatives */
- private final List<Sequence> alternatives = new ArrayList<Sequence>();
-
public Iterator<Sequence> iterator() { return alternatives.iterator(); }
public boolean contains(Sequence s) { return alternatives.contains(s); }
for(Sequence n : s.hates) add(n);
}
- // Epsilon Form //////////////////////////////////////////////////////////////////////////////
- // FIXME
- public static Union epsilon = new Union("()");
- static { epsilon.add(Sequence.empty); }
+ // Epsilon Form //////////////////////////////////////////////////////////////////////////////
// FIXME
- private Forest.Ref epsilonForm = null;
+ private Forest.Many epsilonForm = null;
Forest epsilonForm() {
if (epsilonForm != null) return epsilonForm;
- epsilonForm = new Forest.Ref();
+ epsilonForm = new Forest.Many();
for(Sequence s : this) {
// FIXME FIXME FIXME
if (new Walk.Cache().possiblyEpsilon(s))
return epsilonForm;
}
+
// Display //////////////////////////////////////////////////////////////////////////////
- public String toString() { return shortForm; }
+ public String getName() {
+ if (name != null) return name;
+ return "(anon_union)";
+ }
+ public String toString() {
+ if (name != null) return name;
+ StringBuffer sb = new StringBuffer();
+ sb.append("(");
+ bodyToString(sb, "", " | ");
+ sb.append(")");
+ return sb.toString();
+ }
public StringBuffer toString(StringBuffer sb) {
if (synthetic) return sb;
boolean first = true;
+ String before = StringUtil.pad(15, getName()) + " = ";
if (alternatives.size()==0) {
- sb.append(StringUtil.pad(15, shortForm) + " = ");
- } else for(Sequence s : this) {
- sb.append(StringUtil.pad(15, first ? shortForm : "") + (first ? " = " : " | "));
- first = false;
- sb.append(s.toString());
+ sb.append(before);
+ } else {
+ bodyToString(sb,
+ before,
+ "\n" + StringUtil.pad(15, "") + " | ");
sb.append('\n');
}
- sb.append('\n');
return sb;
}
+
+ 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;
+ sb.append(s.toString());
+ }
+ }
}