lib/collection: better doc for Iterator

[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 d38e001..2f7e454 100644 (file)
--- a/lib/standard/collection/abstract_collection.nit
+++ b/lib/standard/collection/abstract_collection.nit
@@ -66,6 +66,14 @@ interface Collection[E]
        #     assert [1..1[.is_empty   == true
        fun is_empty: Bool do return length == 0
 
+       # Alias for `not is_empty`.
+       #
+       # Some people prefer to have conditions grammatically easier to read.
+       #
+       #     assert [1,2,3].not_empty  == true
+       #     assert [1..1[.not_empty   == false
+       fun not_empty: Bool do return not self.is_empty
+
        # Number of items in the collection.
        #
        #     assert [10,20,30].length == 3
@@ -171,8 +179,9 @@ interface Collection[E]
        end
 end
 
-# Instances of the Iterator class generates a series of elements, one at a time.
-# They are mainly used with collections.
+# Iterators generate a series of elements, one at a time.
+#
+# They are mainly used with collections and obtained from `Collection::iterator`.
 interface Iterator[E]
        # The current item.
        # Require `is_ok`.
@@ -203,7 +212,7 @@ end
 #
 # Used to pass arguments by reference.
 #
-# Also used when one want to give asingle element when a full
+# Also used when one want to give a single element when a full
 # collection is expected
 class Container[E]
        super Collection[E]
@@ -497,6 +506,25 @@ interface MapRead[K, V]
                end
                return true
        end
+
+       # A hashcode based on the hashcode of the keys and the values.
+       #
+       # ~~~
+       # var a = new HashMap[String, Int]
+       # var b = new ArrayMap[Object, Numeric]
+       # a["one"] = 1
+       # b["one"] = 1
+       # assert a.hash == b.hash
+       # ~~~
+       redef fun hash
+       do
+               var res = length
+               for k, v in self do
+                       if k != null then res += k.hash * 7
+                       if v != null then res += v.hash * 11
+               end
+               return res
+       end
 end
 
 # Maps are associative collections: `key` -> `item`.