Fixed minimum parameter count calculation

* the minimum count of parameters to a external function is the maximum parameter count minus all optional parameters
* updated error message of "FunctionBase" member method "getError" to reflect the newly implemented possibility of optional parameters

1 files changed, 2 insertions, 2 deletions

diff --git a/src/support/type/filter.h b/src/support/type/filter.h
index 4a0e19f..1433b30 100644
--- a/src/support/type/filter.h
+++ b/src/support/type/filter.h
@@ -7,13 +7,13 @@
 namespace InputXSLT {
 
 template <
-	typename BaseReference,
+	typename Base,
 	typename Head,
 	typename... Tail
 >
 struct filter_derived {
 	typedef typename std::conditional<
-		std::is_base_of<BaseReference, Head>::value,
+		std::is_base_of<Base, Head>::value,
 		std::tuple<Head, Tail...>,
 		std::tuple<Tail...>
 	>::type type;