From 07c87d1d45af4a3c8111445ab6e6a7863b235d3a Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Thu, 4 May 2017 16:37:00 +0200
Subject: compat: add map/filter template functions

---
 compat/functional.hpp | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 compat/functional.hpp

(limited to 'compat/functional.hpp')

diff --git a/compat/functional.hpp b/compat/functional.hpp
new file mode 100644
index 00000000..e7229d6e
--- /dev/null
+++ b/compat/functional.hpp
@@ -0,0 +1,75 @@
+#pragma once
+
+#include <algorithm>
+#include <iterator>
+#include <type_traits>
+
+namespace functools
+{
+
+constexpr void return_void();
+
+template<typename t>
+using remove_qualifiers = std::remove_reference_t<std::remove_cv_t<t>>;
+
+template<typename seq_, typename = void>
+struct reserver_
+{
+    static inline void maybe_reserve_space(seq_&, unsigned)
+    {
+        //qDebug() << "nada";
+    }
+};
+
+template<typename seq_>
+struct reserver_<seq_, decltype(std::declval<seq_>().reserve(0u), return_void())>
+{
+    static inline void maybe_reserve_space(seq_& seq, unsigned sz)
+    {
+        seq.reserve(sz);
+    }
+};
+
+template<typename seq_>
+inline void maybe_reserve_space(seq_& seq, unsigned sz)
+{
+    reserver_<seq_, void>::maybe_reserve_space(seq, sz);
+}
+
+} // ns
+
+template<typename seq_, typename F>
+auto map(F&& fun, const seq_& seq)
+{
+    using seq_type = functools::remove_qualifiers<seq_>;
+
+    seq_type ret;
+    std::back_insert_iterator<seq_type> it = std::back_inserter(ret);
+
+    for (const auto& elt : seq)
+        it = fun(elt);
+
+    return ret;
+}
+
+template<typename seq_, typename F>
+auto remove_if_not(F&& fun, const seq_& seq)
+{
+    using namespace functools;
+
+    using seq_type = remove_qualifiers<seq_>;
+    using value_type = typename std::iterator_traits<decltype(std::begin(std::declval<seq_>()))>::value_type;
+    using fun_ret_type = decltype(fun(std::declval<const value_type&>()));
+    static_assert(std::is_convertible<fun_ret_type, bool>::value, "must return bool");
+
+    seq_type ret;
+    maybe_reserve_space(ret, seq.size());
+
+    std::back_insert_iterator<seq_type> it = std::back_inserter(ret);
+
+    for (const value_type& elt : seq)
+        if (fun(elt))
+            it = elt;
+
+    return ret;
+}
-- 
cgit v1.2.3


From f8b3c341164fdb336eea43a820af814cff5b6485 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sun, 7 May 2017 11:13:47 +0200
Subject: compat/functional: add generic value-constant type

---
 compat/functional.hpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'compat/functional.hpp')

diff --git a/compat/functional.hpp b/compat/functional.hpp
index e7229d6e..141bbef7 100644
--- a/compat/functional.hpp
+++ b/compat/functional.hpp
@@ -38,6 +38,19 @@ inline void maybe_reserve_space(seq_& seq, unsigned sz)
 
 } // ns
 
+template<typename t, t value_>
+struct constant final
+{
+    using type = t;
+    constexpr type operator()() const noexcept
+    {
+        return value_;
+    }
+    static constexpr type value = value_;
+
+    constant() = delete;
+};
+
 template<typename seq_, typename F>
 auto map(F&& fun, const seq_& seq)
 {
-- 
cgit v1.2.3


From c114e085b3bb51da51c4a7ecceda146e095c7a2e Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sun, 7 May 2017 17:25:43 +0200
Subject: compat/util: simplify

---
 compat/functional.hpp | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

(limited to 'compat/functional.hpp')

diff --git a/compat/functional.hpp b/compat/functional.hpp
index 141bbef7..893fe1a0 100644
--- a/compat/functional.hpp
+++ b/compat/functional.hpp
@@ -4,14 +4,12 @@
 #include <iterator>
 #include <type_traits>
 
-namespace functools
-{
-
-constexpr void return_void();
-
 template<typename t>
 using remove_qualifiers = std::remove_reference_t<std::remove_cv_t<t>>;
 
+namespace functools
+{
+
 template<typename seq_, typename = void>
 struct reserver_
 {
@@ -22,7 +20,7 @@ struct reserver_
 };
 
 template<typename seq_>
-struct reserver_<seq_, decltype(std::declval<seq_>().reserve(0u), return_void())>
+struct reserver_<seq_, decltype(std::declval<seq_>().reserve(0u), (void)0)>
 {
     static inline void maybe_reserve_space(seq_& seq, unsigned sz)
     {
@@ -54,7 +52,7 @@ struct constant final
 template<typename seq_, typename F>
 auto map(F&& fun, const seq_& seq)
 {
-    using seq_type = functools::remove_qualifiers<seq_>;
+    using seq_type = remove_qualifiers<seq_>;
 
     seq_type ret;
     std::back_insert_iterator<seq_type> it = std::back_inserter(ret);
-- 
cgit v1.2.3