feat: add ne and neBy to iterator interface (#92)

Author: uncommon-nickname

include/rusty_iterators/concepts.hpp

@@ -25,6 +25,9 @@ concept EqFunctor = requires(Functor f, std::tuple<T, T> t) {
     { f(t) } -> std::same_as<bool>;
 };
 
+template <class T, class Functor>
+concept NeFunctor = EqFunctor<T, Functor>;
+
 template <class T, class Functor>
 concept FilterFunctor = AllFunctor<T&, Functor>;
 

include/rusty_iterators/interface.hpp

@@ -27,6 +27,7 @@ using concepts::FoldFunctor;
 using concepts::ForEachFunctor;
 using concepts::Indexable;
 using concepts::InspectFunctor;
+using concepts::NeFunctor;
 using concepts::PositionFunctor;
 using concepts::Summable;
 using concepts::TryFoldFunctor;
@@ -123,6 +124,14 @@ class IterInterface
     [[nodiscard]] auto min() -> std::optional<R>;
 
     [[nodiscard]] auto movingWindow(size_t size) -> MovingWindow<T, Derived>;
+
+    template <class Other>
+    [[nodiscard]] auto ne(Other&& it) -> bool;
+
+    template <class Other, class Functor>
+        requires NeFunctor<T, Functor>
+    [[nodiscard]] auto neBy(Other&& it, Functor&& f) -> bool;
+
     [[nodiscard]] auto nth(size_t element) -> std::optional<T>;
 
     template <class Functor>
@@ -355,6 +364,22 @@ auto rusty_iterators::interface::IterInterface<T, Derived>::movingWindow(size_t
     return MovingWindow<T, Derived>{std::forward<Derived>(self()), size};
 }
 
+template <class T, class Derived>
+template <class Other>
+auto rusty_iterators::interface::IterInterface<T, Derived>::ne(Other&& it) -> bool
+{
+    return self().neBy(std::forward<Other>(it),
+                       [](auto x) { return std::get<0>(x) != std::get<1>(x); });
+}
+
+template <class T, class Derived>
+template <class Other, class Functor>
+    requires rusty_iterators::concepts::NeFunctor<T, Functor>
+auto rusty_iterators::interface::IterInterface<T, Derived>::neBy(Other&& it, Functor&& f) -> bool
+{
+    return self().zip(std::forward<Other>(it)).any(std::forward<Functor>(f));
+}
+
 template <class T, class Derived>
 auto rusty_iterators::interface::IterInterface<T, Derived>::nth(size_t element) -> std::optional<T>
 {

tests/iterator.test.cpp

@@ -319,6 +319,34 @@ TEST(TestIterator, TestEqBy)
     ASSERT_TRUE(result);
 }
 
+TEST(TestIterator, TestNeWhenSame)
+{
+    auto v1 = std::vector{1, 2, 3};
+    auto v2 = std::vector{1, 2, 3};
+
+    ASSERT_FALSE(LazyIterator{v1}.ne(LazyIterator{v2}));
+}
+
+TEST(TestIterator, TestNeWhenDifferent)
+{
+    auto v1 = std::vector{1, 2, 3};
+    auto v2 = std::vector{1, 2, 4};
+
+    ASSERT_TRUE(LazyIterator{v1}.ne(LazyIterator{v2}));
+}
+
+TEST(TestIterator, TestNeBy)
+{
+    auto v1 = std::vector<std::string>{"a", "bc", "def"};
+    auto v2 = std::vector<std::string>{"d", "jk", "cgde"};
+
+    auto result = LazyIterator{v1}.neBy(LazyIterator{v2}, [](auto x) {
+        return std::get<0>(x).get().size() != std::get<1>(x).get().size();
+    });
+
+    ASSERT_TRUE(result);
+}
+
 TEST(TestIterator, TestTryFoldEarlyExit)
 {
     auto vec = std::vector{1, 2, 3, 4, 5};