remove unused call_on_nth on tuple

alib2std/src/extensions/common/tuple_common.hpp

@@ -62,32 +62,6 @@ struct tuple_element < I, T && > {
-template < unsigned I >
-struct call_on_nth_helper {
-	template < class Result, class Tuple, class Callable >
-	static Result call_on_nth_fn ( Tuple && t, unsigned index, Callable callback ) {
-		if ( index == 0 )
-			return callback ( std::forward < Tuple && > ( t ).template get < ext::tuple_size < Tuple >::value - I > ( ) );
-		else
-			return call_on_nth_helper < I - 1 >::template call_on_nth_fn < Result > ( std::forward < Tuple && > ( t ), index - 1, callback );
-	}
-};
-
-template < >
-struct call_on_nth_helper < 0 > {
-	template < class Result, class Tuple, class Callable >
-	static Result call_on_nth_fn ( Tuple &&, unsigned, Callable ) {
-		throw std::out_of_range ( "Not enough elements in tuple." );
-	}
-};
-
-template < class Result, class Tuple, class Callable >
-Result call_on_nth ( Tuple && t, unsigned index, Callable callback ) {
-	return call_on_nth_helper < ext::tuple_size < Tuple >::value >::template call_on_nth_fn < Result > ( std::forward < Tuple && > ( t ), index, callback );
-}
-
-
-
 template < unsigned I >
 struct foreach_helper {
 	template < class Tuple, class Callable >

alib2std/test-src/extensions/container/PtrTupleTest.cpp

@@ -6,8 +6,6 @@ TEST_CASE ( "PtrTuple", "[unit][std][container]" ) {
 	SECTION ( "Test call on nth" ) {
 		ext::ptr_tuple < int, int, int, int, int > t = ext::make_ptr_tuple ( 1, 2, 3, 4, 5 );
-		CHECK ( ext::call_on_nth < int > ( t, 1, [] ( int i ) { return i; } ) == 2 );
-
 		std::stringstream ss;
 		ss << t;
 		CAPTURE ( ss.str ( ) );

alib2std/test-src/extensions/container/TupleTest.cpp

@@ -6,8 +6,6 @@ TEST_CASE ( "Tuple", "[unit][std][container]" ) {
 	SECTION ( "Test call on nth" ) {
 		ext::tuple < int, int, int, int, int > t = ext::make_tuple ( 1, 2, 3, 4, 5 );
-		CHECK ( ext::call_on_nth < int > ( t, 1, [] ( int i ) { return i; } ) == 2 );
-
 		std::stringstream ss;
 		ss << t;
 		CAPTURE ( ss.str ( ) );