Reimplemented `Find` in terms of `ListIndex`

* `ListIndex` already implements the necessary partial template specializations for finding elements matching a predicate
* reimplemented `Cond` using `detail::find_variadic` as `Find` depends on `Apply` which in turn depends on `Cond`
** it is useful if core functionality such as the branched conditional `Cond` do not require higher order functionality such as `Find`
*** otherwise one can not use core functionality in the implementation of higher order functionality
* introduced `utility::predicate_guard` helper template
** checks a given value using a predicate and only forwards the value to the guarded function if this check is successful
** if check is unsuccessful it returns a surrogate value simmilar to `utility::predicate_assurance`

1 files changed, 12 insertions, 26 deletions

diff --git a/src/list/operation/higher/find.h b/src/list/operation/higher/find.h
index 48533b7..aeb0c2a 100644
--- a/src/list/operation/higher/find.h
+++ b/src/list/operation/higher/find.h
@@ -1,39 +1,25 @@
 #ifndef TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_FIND_H_
 #define TYPEASVALUE_SRC_LIST_OPERATION_HIGHER_FIND_H_
 
-#include "type.h"
-#include "conditional/if.h"
+#include "utility/predicate.h"
+#include "function/apply.h"
+#include "list/operation/nth.h"
+#include "list_index.h"
 
 namespace tav {
 
-namespace detail {
-
-template <
-	template<typename> class Predicate,
-	typename                 Current
->
-struct Find {
-	typedef If<
-		Eval<Predicate<Head<Current>>>,
-		Head<Current>,
-		Eval<Find<Predicate, Tail<Current>>>
-	> type;
-};
-
-template <
-	template<typename> class Predicate
->
-struct Find<Predicate, void> {
-	typedef Boolean<false> type;
-};
-
-}
-
 template <
 	template<typename> class Predicate,
 	typename                 List
 >
-using Find = Eval<detail::Find<Predicate, List>>;
+using Find = typename utility::predicate_guard<
+	IsSize,
+	Apply<Nth, _0, List>::template function,
+	Boolean<false>
+>::template check<
+	ListIndex<Predicate, List>
+>;
+
 
 }