From 1f910a8a87b8e243ef92255295c3b7e02f2bae54 Mon Sep 17 00:00:00 2001
From: Kris Jusiak <kris@jusiak.net>
Date: Sun, 18 Jun 2023 13:01:53 -0500
Subject: [PATCH] [335] - Did you know that you can simplify `boost.mp11` API
 with DSL?

---
 README.md   | 11 +++++-----
 tips/334.md | 15 +++++++------
 tips/335.md | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 12 deletions(-)
 create mode 100644 tips/335.md

diff --git a/README.md b/README.md
index 7382ef6..e15ee63 100644
--- a/README.md
+++ b/README.md
@@ -12,12 +12,13 @@
 
 ### Tips
 
-* [[334]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/334.md) - Did you know that C++23 added std::invoke_r?
-* [[333]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/333.md) - Did you know that C++20 added std::span?
+* [[335]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/335.md) - Did you know that you can simplify `boost.mp11` API with DSL?
+* [[334]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/334.md) - Did you know that C++23 added `std::invoke_r`?
+* [[333]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/333.md) - Did you know that C++20 added `std::span`?
 * [[332]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/332.md) - Did you know that in C++ you can generate jump tables at compile-time?
-* [[331]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/331.md) - Did you about C++17 std::index_sequence, std::make_index_sequence?
-* [[330]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/330.md) - Did you know that C++17 added std::pmr::polymorphic_allocator?
-* [[329]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/329.md) - Did you know about C++ allows to pass Pointer To Member Function via template parameter?
+* [[331]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/331.md) - Did you about C++17 `std::index_sequence, std::make_index_sequence`?
+* [[330]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/330.md) - Did you know that C++17 added `std::pmr::polymorphic_allocator`?
+* [[329]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/329.md) - Did you know that C++ allows to pass Pointer To Member Function via template parameter?
 * [[328]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/328.md) - Did you know that C++23 extended floating-point types?
 * [[327]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/327.md) - Did you know that C++17 added `std::forward_as_tuple` and `std::make_from_tuple` and what’s the difference between them?
 * [[326]](https://github.com/QuantlabFinancial/cpp_tip_of_the_week/blob/master/tips/326.md) - Did you know that C++23 deprecated std::aligned_storage and std::aligned_union?
diff --git a/tips/334.md b/tips/334.md
index f28321c..d80d986 100644
--- a/tips/334.md
+++ b/tips/334.md
@@ -42,11 +42,6 @@ static_assert(typeid(unsigned long long) == typeid(call(1ll, 2ull, 3l)));
 </p></details><details><summary>Solutions</summary><p>
 
 ```cpp
-#include <functional>
-#include <type_traits>
-
-constexpr auto sum(auto... ts) { return (ts + ...); }
-
 [[nodiscard]] constexpr auto call(auto... ts) {
     using Ret = std::common_type_t<decltype(ts)...>;
     return std::invoke_r<Ret>(sum<decltype(ts)...>, ts...);
@@ -55,7 +50,13 @@ constexpr auto sum(auto... ts) { return (ts + ...); }
 
 > https://godbolt.org/z/1baMcc331
 
-</p></details>
-<details><summary>Solutions</summary><p>
+```cpp
+[[nodiscard]] constexpr auto call(auto... ts){
+    using T = typename std::common_type_t<decltype(ts)...>;
+    return std::invoke_r<T>(&sum<decltype(ts)...>, ts...);
+}
+```
+
 > https://godbolt.org/z/xcn9qnrcY
+
 </p></details>
diff --git a/tips/335.md b/tips/335.md
new file mode 100644
index 0000000..85b40d7
--- /dev/null
+++ b/tips/335.md
@@ -0,0 +1,61 @@
+<details open><summary>Info</summary><p>
+
+* Did you know that you can simplify `boost.mp11` API with DSL*?
+
+  * https://github.com/boostorg/mp11
+  * DSL - Domain Specific Language
+
+</p></details><details open><summary>Example</summary><p>
+
+```cpp
+template <class T1, class T2>
+[[nodiscard]] constexpr auto operator==(const T1&, const T2&) { return std::is_same_v<T1, T2>; }
+
+template <class... Ts>
+constexpr auto list = mp11::mp_list<Ts...>{};
+
+static_assert(list<> == list<>);
+static_assert(list<int> == list<int>);
+static_assert(list<int, double> == list<int, double>);
+```
+
+> https://godbolt.org/z/fTMsK8Moh
+
+</p></details><details open><summary>Puzzle</summary><p>
+
+* Can you implement DSL for boost.mp11
+
+```cpp
+struct event {};
+class foo1 : event {};
+class foo2 : event { int i; };
+class bar1 {};
+class bar2 { int i; };
+
+template<class... Ts>
+constexpr auto unique_event_ptrs =
+    list<Ts...>
+  | unique
+  | filter<is_base_of<event>>
+  | transform<add_pointer>
+  ;
+
+static_assert(unique_event_ptrs<> == list<>);
+static_assert(unique_event_ptrs<foo1> == list<foo1*>);
+static_assert(unique_event_ptrs<foo1, foo1> == list<foo1*>);
+static_assert(unique_event_ptrs<bar1> == list<>);
+static_assert(unique_event_ptrs<bar1, bar1> == list<>);
+static_assert(unique_event_ptrs<bar2, bar1> == list<>);
+static_assert(unique_event_ptrs<foo2, foo1> == list<foo2*, foo1*>);
+static_assert(unique_event_ptrs<foo1, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, foo2, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, foo1, foo2, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, foo2, foo1, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, bar1, foo1, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, bar1, foo1, foo2> == list<foo1*, foo2*>);
+static_assert(unique_event_ptrs<foo1, bar1, foo1, foo1, bar1, bar2> == list<foo1*>);
+```
+
+> https://godbolt.org/z/rjh6hhK6j
+
+</p></details>