tmp/tmp_njb2545/{from.md → to.md}
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| 1 |
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#### Accessors <a id="common.iter.access">[[common.iter.access]]</a>
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``` cpp
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decltype(auto) operator*();
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decltype(auto) operator*() const
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requires dereferenceable<const I>;
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```
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*Preconditions:* `holds_alternative<I>(v_)`.
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*Effects:* Equivalent to: `return *get<I>(v_);`
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``` cpp
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decltype(auto) operator->() const
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requires see below;
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```
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The expression in the requires clause is equivalent to:
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``` cpp
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indirectly_readable<const I> &&
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(requires(const I& i) { i.operator->(); } ||
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is_reference_v<iter_reference_t<I>> ||
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constructible_from<iter_value_t<I>, iter_reference_t<I>>)
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```
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*Preconditions:* `holds_alternative<I>(v_)`.
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*Effects:*
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- If `I` is a pointer type or if the expression
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`get<I>(v_).operator->()` is well-formed, equivalent to:
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`return get<I>(v_);`
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- Otherwise, if `iter_reference_t<I>` is a reference type, equivalent
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to:
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``` cpp
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auto&& tmp = *get<I>(v_);
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return addressof(tmp);
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```
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- Otherwise, equivalent to: `return `*`proxy`*`(*get<I>(v_));` where
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*proxy* is the exposition-only class:
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``` cpp
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class proxy {
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iter_value_t<I> keep_;
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proxy(iter_reference_t<I>&& x)
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: keep_(std::move(x)) {}
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public:
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const iter_value_t<I>* operator->() const {
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return addressof(keep_);
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}
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};
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```
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