Merge: lib/string: some cleaning, doc and unit tests

[nit.git] / lib / standard / collection / abstract_collection.nit

diff --git a/lib/standard/collection/abstract_collection.nit b/lib/standard/collection/abstract_collection.nit
index f693ac1..20be476 100644 (file)
--- a/lib/standard/collection/abstract_collection.nit
+++ b/lib/standard/collection/abstract_collection.nit
@@ -653,8 +653,6 @@ interface SequenceRead[E]
                return res
        end
 
-       redef fun iterator: IndexedIterator[E] is abstract
-
        # Two sequences are equals if they have the same items in the same order.
        #
        #     var a = new List[Int]
@@ -683,6 +681,42 @@ interface SequenceRead[E]
                for e in self do res += res.hash
                return res
        end
+
+       redef fun iterator: IndexedIterator[E] is abstract
+
+       # Gets a new Iterator starting at position `pos`
+       #
+       #     var iter = [10,20,30,40,50].iterator_from(2)
+       #     assert iter.to_a == [30, 40, 50]
+       fun iterator_from(pos: Int): IndexedIterator[E]
+       do
+               var res = iterator
+               while pos > 0 and res.is_ok do
+                       res.next
+                       pos -= 1
+               end
+               return res
+       end
+
+       # Gets an iterator starting at the end and going backwards
+       #
+       #     var reviter = [1,2,3].reverse_iterator
+       #     assert reviter.to_a == [3,2,1]
+       fun reverse_iterator: IndexedIterator[E] is abstract
+
+       # Gets an iterator on the chars of self starting from `pos`
+       #
+       #     var reviter = [10,20,30,40,50].reverse_iterator_from(2)
+       #     assert reviter.to_a == [30,20,10]
+       fun reverse_iterator_from(pos: Int): IndexedIterator[E]
+       do
+               var res = reverse_iterator
+               while pos > 0 and res.is_ok do
+                       res.next
+                       pos -= 1
+               end
+               return res
+       end
 end
 
 # Sequence are indexed collection.