gsl::at overload for initializer_list
initializer_list do not have subscript operator, so the generic container overload of gsl::at fails to compile.
This commits adds an overload of gsl::at for initializer_lists, using *(initializer_list::begin()+index) instead of subscript operator
diff --git a/include/gsl_util.h b/include/gsl_util.h
index edfcce4..b42b66a 100644
--- a/include/gsl_util.h
+++ b/include/gsl_util.h
@@ -128,6 +128,10 @@
constexpr typename Cont::value_type& at(Cont& cont, size_t index)
{ Expects(index < cont.size()); return cont[index]; }
+template <class T>
+constexpr const T& at(std::initializer_list<T> cont, size_t index)
+{ Expects(index < cont.size()); return *(cont.begin() + index); }
+
} // namespace gsl
diff --git a/tests/at_tests.cpp b/tests/at_tests.cpp
index d27dd9d..1a9f814 100644
--- a/tests/at_tests.cpp
+++ b/tests/at_tests.cpp
@@ -17,6 +17,7 @@
#include <UnitTest++/UnitTest++.h>
#include <gsl.h>
#include <vector>
+#include <initializer_list>
using namespace std;
using namespace gsl;
@@ -52,6 +53,16 @@
CHECK_THROW(at(a, 4), fail_fast);
}
+
+ TEST(InitializerList)
+ {
+ std::initializer_list<int> a = { 1, 2, 3, 4 };
+
+ for (int i = 0; i < 4; ++i)
+ CHECK(at(a, i) == i+1);
+
+ CHECK_THROW(at(a, 4), fail_fast);
+ }
}
int main(int, const char *[])