# Filter: sort with a given `comparator`.
# Important: require O(n) memory.
#
- # assert ["a", "c", "b"].iterator.sort_with(alpha_comparator).to_a == ["a", "b", "c"]
+ # assert ["a", "c", "b"].iterator.sort_with(alpha_comparator).to_a == ["a", "b", "c"]
fun sort_with(comparator: Comparator): Iterator[E]
do
var a = self.to_a
# Alternate each item with `e`.
#
- # assert [1,2,3].iterator.alternate(0).to_a == [1,0,2,0,3]
+ # assert [1,2,3].iterator.alternate(0).to_a == [1,0,2,0,3]
fun alternate(e: E): Iterator[E]
do
return new PipeAlternate[E](self, e)
# Filter: reject a given `item`.
#
- # assert [1,1,2,1,3].iterator.skip(1).to_a == [2,3]
+ # assert [1,1,2,1,3].iterator.skip(1).to_a == [2,3]
fun skip(item: E): Iterator[E]
do
return new PipeSkip[E](self, item)
end
end
+# Wraps an iterator to skip nulls.
+#
+# ~~~nit
+# var i: Iterator[Int]
+#
+# i = new NullSkipper[Int]([null, 1, null, 2, null: nullable Int].iterator)
+# assert i.to_a == [1, 2]
+#
+# i = new NullSkipper[Int]([1, null, 2, 3: nullable Int].iterator)
+# assert i.to_a == [1, 2, 3]
+# ~~~
+class NullSkipper[E: Object]
+ super Iterator[E]
+
+ # The inner iterator.
+ var inner: Iterator[nullable E]
+
+ redef fun finish do inner.finish
+
+ redef fun is_ok do
+ skip_nulls
+ return inner.is_ok
+ end
+
+ redef fun item do
+ skip_nulls
+ return inner.item.as(E)
+ end
+
+ redef fun next do
+ inner.next
+ skip_nulls
+ end
+
+ private fun skip_nulls do
+ while inner.is_ok and inner.item == null do inner.next
+ end
+end
+
# Interface that reify a function.
# Concrete subclasses must implements the `apply` method.
#