sclass WithCount<A> extends Var<A> {
  int count;
  
  *() {}
  *(int *count, A value) { super(value); }
  *(A value) { super(value); }
  *(A value, int *count) { super(value); }
  
  int count() { ret count; }
  
  toString { ret super.toString() + appendBracketed(n2(count)); }
}

Began life as a copy of #1026686