public void expand(HashSet<Tree<NodeType>> ht) { expand(ht, new HashSet<Forest<NodeType>>(), null); }
static <NodeType> Forest<NodeType> create(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
- if (loc == null) throw new Error();
+ if (loc == null) throw new RuntimeException("invoked Forest.create(null,,,,) -- this should never happen");
return new One<NodeType>(loc, head, children, lift);
}
private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
this.location = loc;
this.head = head;
+ if (head==null) throw new RuntimeException("invoked Forest.create(,null,,,) -- this should never happen");
this.children = children==null ? emptyForestArray : new Forest[children.length];
if (children != null) System.arraycopy(children, 0, this.children, 0, children.length);
if (children != null) for(int i=0; i<children.length; i++) if (children[i]==null) throw new Error(i+"");
/** An "ambiguity node"; this is immutable once it has been "looked at" */
static class Many<NodeType> extends Forest<NodeType> {
- HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
private FastSet<Forest<NodeType>> hp = new FastSet<Forest<NodeType>>();
private boolean touched = false;
void gather(HashSet<Forest<NodeType>> ht) {
touched();
+
+ // FIXME: do something more sensible here
+ if (ht.contains(this)) {
+ System.err.println("WARNING: grammar produced a circular forest\n" + this);
+ //throw new Error("grammar produced a circular forest:\n" + this);
+ return;
+ }
+
ht.add(this);
for(Forest<NodeType> f : hp) f.gather(ht);
}