collection: implements `MapRead::==`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/standard/collection/abstract_collection.nit b/lib/standard/collection/abstract_collection.nit
index 858d569..20d1584 100644 (file)
--- a/lib/standard/collection/abstract_collection.nit
+++ b/lib/standard/collection/abstract_collection.nit
@@ -466,6 +466,30 @@ interface MapRead[K, V]
        # Note: the value is returned *as is*, implementations may want to store the value in the map before returning it
        # @toimplement
        protected fun provide_default_value(key: K): V do abort
+
+       # Does `self` and `other` have the same keys associated with the same values?
+       #
+       # ~~~
+       # var a = new HashMap[String, Int]
+       # var b = new ArrayMap[Object, Numeric]
+       # assert a == b
+       # a["one"] = 1
+       # assert a != b
+       # b["one"] = 1
+       # assert a == b
+       # b["one"] = 2
+       # assert a != b
+       # ~~~
+       redef fun ==(other)
+       do
+               if not other isa MapRead[nullable Object, nullable Object] then return false
+               if other.length != self.length then return false
+               for k, v in self do
+                       if not other.has_key(k) then return false
+                       if other[k] != v then return false
+               end
+               return true
+       end
 end
 
 # Maps are associative collections: `key` -> `item`.