From bcb4d7569f75bd2da5591b7df218dbbca2109697 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Wed, 1 Aug 2018 18:39:01 +1000
Subject: [PATCH] types/traits: add is_same_basic_type trait

---
 test/traits.cpp  |  4 ++++
 types/traits.hpp | 58 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/test/traits.cpp b/test/traits.cpp
index cc7b6c31..e5c97200 100644
--- a/test/traits.cpp
+++ b/test/traits.cpp
@@ -63,5 +63,9 @@ main (void)
     tap.expect (is_contiguous_v<std::vector<char>>, "vector is contiguous");
     tap.expect (is_contiguous_v<std::array<char,4>>, "array is contiguous");
     tap.expect (!is_contiguous_v<std::list<char>>, "list is not contiguous");
+
+
+    tap.expect ( util::is_same_basic_type_v<float,double>, "float-double same_basic_type");
+    tap.expect (!util::is_same_basic_type_v<float,int>,    "float-int same_basic_type");
     return tap.status ();
 }
\ No newline at end of file
diff --git a/types/traits.hpp b/types/traits.hpp
index e407af52..4ba6198f 100644
--- a/types/traits.hpp
+++ b/types/traits.hpp
@@ -27,7 +27,7 @@
 /// modifiers are applied in the order they are provided.
 ///
 /// use without any modifiers results in the identity modifier.
-namespace util {
+namespace util::types {
     //-------------------------------------------------------------------------
     template <typename TypeT, template <typename> class ...ModifierT>
     struct compose;
@@ -260,7 +260,7 @@ template <typename T>
 struct func_traits : public ::detail::func_traits<
     // we apply as many transforms as possible before palming it off to the
     // detail class so that we don't have to write as many distinct cases.
-    ::util::chain_t<T,
+    ::util::types::chain_t<T,
         std::remove_cv,
         std::decay,
         remove_member_const,
@@ -405,4 +405,58 @@ template <
 template <template <typename...> class TemplateT, typename QueryT>
 constexpr auto is_same_template_template_v = is_same_template_template<TemplateT,QueryT>::value;
 
+
+namespace util::traits {
+    /// combines an abitrary sequence of type traits into one result
+    template <
+        typename ValueT,
+        template <typename> class ...Traits
+    > struct all : public std::integral_constant<
+        bool,
+        (Traits<ValueT>::value && ...)
+    > { };
+};
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+namespace util {
+    /// tests if the type is a signed integer type
+    template <typename ValueT>
+    struct is_signed_integral : public traits::all<
+        ValueT, std::is_signed, std::is_integral
+    > { };
+
+
+    template <typename ValueT>
+    constexpr auto is_signed_integral_v = is_signed_integral<ValueT>::value;
+
+
+    /// tests if the type is an unsigned integer type
+    template <typename ValueT>
+    struct is_unsigned_integral : public traits::all<
+        ValueT, std::is_unsigned, std::is_integral
+    > { };
+
+    template <typename ValueT>
+    constexpr auto is_unsigned_integral_v = is_unsigned_integral<ValueT>::value;
+
+
+    /// tests if the type has the same basic fundamental type.
+    ///
+    /// ie, both float, signed, unsigned, or char.
+    template <typename ValueA, typename ValueB>
+    struct is_same_basic_type {
+        static constexpr bool value =
+            (std::is_floating_point_v<ValueA> && std::is_floating_point_v<ValueB>) ||
+            (is_unsigned_integral_v<ValueA>   && is_unsigned_integral_v<ValueB>) ||
+            (is_signed_integral_v<ValueA>     && is_signed_integral_v<ValueB>) ||
+            (std::is_same_v<char,ValueA>      && std::is_same_v<char,ValueB>);
+    };
+
+
+    template <typename ValueA, typename ValueB>
+    constexpr auto is_same_basic_type_v = is_same_basic_type<ValueA,ValueB>::value;
+}
+
 #endif