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Merge pull request #71 from grisumbras/feature/mp_valid_and_true

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implement mp_valid_and_true
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Peter Dimov
2022-02-17 00:12:05 +02:00
committed by GitHub
parent 28036d0bdb 1336c4f9c3
commit 7bc4e1ae9b
4 changed files with 67 additions and 0 deletions
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doc/mp11/utility.adoc
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@@ -188,6 +188,20 @@ template<class... T> using first_or_void =
Like `mp_eval_or`, but takes a quoted metafunction.
## mp_valid_and_true<F, T...>
template<template<class...> class F, class... T> using mp_valid_and_true =
mp_eval_or<mp_false, F, T...>;
`mp_valid_and_true<F, T...>` is an alias for `F<T...>` when this expression is valid, for `mp_false` otherwise.
## mp_valid_and_true_q<Q, T...>
template<class Q, class... T> using mp_valid_and_true_q =
mp_valid_and_true<Q::template fn, T...>;
Like `mp_valid_and_true`, but takes a quoted metafunction.
## mp_cond<C, T, R...>
template<class C, class T, class... R> using mp_cond = /*...*/;