diff options
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`
Diffstat (limited to 'src/list/detail/find_variadic.h')
| -rw-r--r-- | src/list/detail/find_variadic.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/src/list/detail/find_variadic.h b/src/list/detail/find_variadic.h new file mode 100644 index 0000000..824f385 --- /dev/null +++ b/src/list/detail/find_variadic.h @@ -0,0 +1,40 @@ +#ifndef TYPEASVALUE_SRC_LIST_DETAIL_FIND_VARIADIC_H_ +#define TYPEASVALUE_SRC_LIST_DETAIL_FIND_VARIADIC_H_ + +#include "type.h" +#include "conditional/if.h" + +namespace tav { + +namespace detail { + +template < + template<typename> class Predicate, + typename Head, + typename... Tail +> +struct find_variadic { + typedef If< + Eval<Predicate<Head>>, + Head, + Eval<find_variadic<Predicate, Tail...>> + > type; +}; + +template < + template<typename> class Predicate, + typename Last +> +struct find_variadic<Predicate, Last> { + typedef If< + Eval<Predicate<Last>>, + Last, + void + > type; +}; + +} + +} + +#endif // TYPEASVALUE_SRC_LIST_DETAIL_FIND_VARIADIC_H_ |