is_sequence_concept impl

include/jwt/detail/meta.hpp

@@ -1,6 +1,7 @@
 #ifndef CPP_JWT_META_HPP
 #define CPP_JWT_META_HPP
 
+#include <iterator>
 #include <type_traits>
 #include "jwt/string_view.hpp"
 
@@ -123,17 +124,42 @@ struct is_parameter_concept<T,
 
 /**
  */
-/*
+
 template <typename T, typename=void>
 struct is_sequence_concept: std::false_type
 {
 };
 
+/// For array types
 template <typename T>
-struct is_sequence_concept<>: std::true_type
+struct is_sequence_concept<T,
+  void_t<
+    std::enable_if_t<std::is_array<std::decay_t<T>>::value>
+  >
+  >: std::true_type
 {
 };
-*/
+
+template <typename T>
+struct is_sequence_concept<T,
+  void_t<
+    std::enable_if_t<
+      std::is_base_of<
+        std::forward_iterator_tag,
+        typename std::remove_reference_t<T>::iterator::iterator_category
+      >::value
+    >,
+
+    decltype(
+      std::declval<T&>().begin(),
+      std::declval<T&>().end(),
+      (void)0
+    )
+  >
+  >: std::true_type
+{
+};
+
 
 /**
  * Find if a type is present in the typelist.

include/jwt/test/test_jwt_object.cc

@@ -49,6 +49,8 @@ void basic_jwt_object_test()
 
 void jwt_object_pem_test()
 {
+  using namespace jwt::params;
+
   std::string pub_key = 
     R"(-----BEGIN PUBLIC KEY-----
 MHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEomxC9ycc8AkXSwWQpu1kN5Fmgy/sD/KJ
@@ -75,6 +77,8 @@ MIGkAgEBBDBeLCgapjZmvTatMHaYX3A02+0Ys3Tr8kda+E9DFnmCSiCOEig519fT
      ;
 
   std::cout << "pem sign " << obj.signature() << std::endl;
+  auto dec_obj = jwt::decode(obj.signature(), pub_key, algorithms({"es256"}));
+  std::cout << dec_obj.payload() << std::endl;
 }
 
 int main() {