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| author | Adrian Kummerlaender | 2015-02-25 18:47:56 +0100 |
|---|---|---|
| committer | Adrian Kummerlaender | 2015-02-25 18:47:56 +0100 |
| commit | e26621df352272688834361e7d026338cefb1372 (patch) | |
| tree | 46064b5d0373e0b177791feaeaac86db086a685d /src | |
| parent | a3a0d6a1fa880b324576bb073637e021c57b0e65 (diff) | |
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Added `Cond` branch condition assertion
* improves error messages in case no branch condition resolves to `true`
Diffstat (limited to 'src')
| -rw-r--r-- | src/conditional/cond.h | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/src/conditional/cond.h b/src/conditional/cond.h index 5f8014f..ca5e46d 100644 --- a/src/conditional/cond.h +++ b/src/conditional/cond.h @@ -12,12 +12,20 @@ namespace detail { template <typename Pair> using cond_predicate = IsTrue<Car<Pair>>; +template <typename... Branches> +struct select_cond_branch { + using type = Eval<detail::find_variadic<detail::cond_predicate, Branches...>>; + + static_assert( + IsPair<type>::value, + "all branch conditions resolve to false" + ); +}; + } template <typename... Branches> -using Cond = Cdr<Eval< - detail::find_variadic<detail::cond_predicate, Branches...> ->>; +using Cond = Cdr<Eval<detail::select_cond_branch<Branches...>>>; template < typename Condition, |