22 lines
681 B
Plaintext
22 lines
681 B
Plaintext
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[#boxed_value]
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[section Boxed value]
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A ['boxed value] is a type representing a constant value. It has a public static
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`const` or `constexpr` member called `value`. The class represents that value as
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a type, so it can be manipulated by [link metafunction template metafunction]s.
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It has to be a [link metaprogramming_value template metaprogramming value].
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For example the following `struct` represents the `true` value of type `bool`:
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struct true_type
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{
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static constexpr bool value = true;
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using type = true_type;
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};
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The `value` member is the wrapped value. `true_type::type` is an alias of
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`true_type` which makes it a template metaprogramming value.
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[endsect]
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