From 3b74b817ec6edd226f8bfd2cd3d01a96291d94b4 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Wed, 10 May 2017 23:31:28 +0200
Subject: [PATCH] Add trait to test for strings

---
 misc/traits.h         |  7 +++++++
 tests/traitstests.cpp | 12 ++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/misc/traits.h b/misc/traits.h
index ee07725..909be12 100644
--- a/misc/traits.h
+++ b/misc/traits.h
@@ -41,6 +41,13 @@ template <typename T, template <typename...> class Template> struct IsSpecializa
 template <template <typename...> class Template, typename... Args> struct IsSpecializationOf<Template<Args...>, Template> : Bool<true> {
 };
 
+template <typename T>
+struct IsCString
+    : Bool<std::is_same<char const *, typename std::decay<T>::type>::value || std::is_same<char *, typename std::decay<T>::type>::value> {
+};
+template <typename T> struct IsString : Bool<IsCString<T>::value || IsSpecializationOf<T, std::basic_string>::value> {
+};
+
 /// \cond
 namespace Detail {
 // allow ADL with custom begin/end
diff --git a/tests/traitstests.cpp b/tests/traitstests.cpp
index 7111e08..7bad8aa 100644
--- a/tests/traitstests.cpp
+++ b/tests/traitstests.cpp
@@ -31,3 +31,15 @@ static_assert(IsIteratable<vector<int>>::value, "IsIterator: positive case");
 static_assert(IsIteratable<list<string>>::value, "IsIterator: positive case");
 static_assert(IsIteratable<map<string, string>>::value, "IsIterator: positive case");
 static_assert(IsIteratable<initializer_list<double>>::value, "IsIterator: positive case");
+
+static_assert(!IsCString<string>::value, "IsCString: negative case");
+static_assert(!IsCString<int[]>::value, "IsCString: negative case");
+static_assert(!IsCString<int *>::value, "IsCString: negative case");
+static_assert(IsCString<char[]>::value, "IsCString: positive case");
+static_assert(IsCString<char *>::value, "IsCString: positive case");
+static_assert(IsCString<const char *>::value, "IsCString: positive case");
+static_assert(!IsString<int *>::value, "IsString: negative case");
+static_assert(!IsString<stringstream>::value, "IsString: negative case");
+static_assert(IsString<const char *>::value, "IsString: positive case");
+static_assert(IsString<string>::value, "IsCString: positive case");
+static_assert(IsString<u16string>::value, "IsCString: positive case");