iterator.html

<cxx-clause id="iterator">
  <h1>Iterators library</h1>

  <cxx-section id="iterator.syn">
    <h1>Header <code>&lt;experimental/iterator></code> synopsis</h1>

<pre><code>#include &lt;iterator>

namespace std::experimental::inline fundamentals_v3 {

  <cxx-ref insynopsis="" to="iterator.ostream.joiner"></cxx-ref>
  template &lt;class DelimT, class charT = char, class traits = char_traits&lt;charT>>
      class ostream_joiner;
  template &lt;class charT, class traits, class DelimT>
    ostream_joiner&lt;decay_t&lt;DelimT>, charT, traits>
    make_ostream_joiner(basic_ostream&lt;charT, traits>&amp; os, DelimT&amp;&amp; delimiter);

} // namespace std::experimental::inline fundamentals_v3</code></pre>
  </cxx-section>

  <cxx-section id="iterator.ostream.joiner">
    <h1>Class template <code>ostream_joiner</code></h1>

    <cxx-section id="iterator.ostream.joiner.overview">
      <h1>Overview</h1>

      <p>
        <code>ostream_joiner</code> writes (using <code>operator&lt;&lt;</code>) successive elements onto the output stream from which it was constructed.
        The delimiter that it was constructed with is written to the stream between every two <code>T</code>s that are written.
        It is not possible to get a value out of the output iterator.
        Its only use is as an output iterator in situations like
      </p>
      <pre><code>while (first != last)
  *result++ = *first++;</code></pre>

      <p>
        <code>ostream_joiner</code> is defined as
      </p>
      <pre><code>namespace std::experimental::inline fundamentals_v3 {

  template &lt;class DelimT, class charT = char, class traits = char_traits&lt;charT&gt;&gt;
  class ostream_joiner {
  public:
    using char_type = charT;
    using traits_type = traits;
    using ostream_type = basic_ostream&lt;charT, traits&gt;;
    using iterator_category = output_iterator_tag;
    using value_type = void;
    using difference_type = void;
    using pointer = void;
    using reference = void;

    ostream_joiner(ostream_type&amp; s, const DelimT&amp; delimiter);
    ostream_joiner(ostream_type&amp; s, DelimT&amp;&amp; delimiter);
    template&lt;typename T&gt;
    ostream_joiner&amp; operator=(const T&amp; value);
    ostream_joiner&amp; operator*() noexcept;
    ostream_joiner&amp; operator++() noexcept;
    ostream_joiner&amp; operator++(int) noexcept;

  private:
    ostream_type* out_stream; <i>// exposition only</i>
    DelimT delim;             <i>// exposition only</i>
    bool first_element;       <i>// exposition only</i>
  };

} // namespace std::experimental::inline fundamentals_v3</code></pre>
    </cxx-section>

    <cxx-section id="iterator.ostream.joiner.cons">
      <h1>Constructor</h1>

      <cxx-function>
        <cxx-signature>ostream_joiner(ostream_type&amp; s, const DelimT&amp; delimiter);</cxx-signature>

        <cxx-effects>
          Initializes <code>out_stream</code> with <code>std::addressof(s)</code>,
          <code>delim</code> with <code>delimiter</code>,
          and <code>first_element</code> with <code>true</code>.
        </cxx-effects>
      </cxx-function>

      <cxx-function>
        <cxx-signature>ostream_joiner(ostream_type&amp; s, DelimT&amp;&amp; delimiter);</cxx-signature>

        <cxx-effects>
          Initializes <code>out_stream</code> with <code>std::addressof(s)</code>,
          <code>delim</code> with <code>move(delimiter)</code>,
          and <code>first_element</code> with <code>true</code>.
        </cxx-effects>
      </cxx-function>
    </cxx-section>

    <cxx-section id="iterator.ostream.joiner.ops">
      <h1>Operations</h1>

      <cxx-function>
        <cxx-signature>template&lt;typename T&gt;
ostream_joiner&amp; operator=(const T&amp; value);</cxx-signature>

        <cxx-effects>
          <pre style="clear:left"><code>if (!first_element)
  *out_stream &lt;&lt; delim;
first_element = false;
*out_stream &lt;&lt; value;
return *this;</code></pre>
        </cxx-effects>
      </cxx-function>

      <cxx-function>
        <cxx-signature>ostream_joiner&amp; operator*() noexcept;</cxx-signature>

        <cxx-returns><code>*this</code>.</cxx-returns>
      </cxx-function>

      <cxx-function>
        <cxx-signature>ostream_joiner&amp; operator++() noexcept;</cxx-signature>
        <cxx-signature>ostream_joiner&amp; operator++(int) noexcept;</cxx-signature>

        <cxx-returns><code>*this</code>.</cxx-returns>
      </cxx-function>
    </cxx-section>

    <cxx-section id="iterator.ostream.joiner.creation">
      <h1>Creation function</h1>

      <cxx-function>
        <cxx-signature>template &lt;class charT, class traits, class DelimT&gt;
ostream_joiner&lt;decay_t&lt;DelimT&gt;, charT, traits&gt;
make_ostream_joiner(basic_ostream&lt;charT, traits&gt;&amp; os, DelimT&amp;&amp; delimiter);</cxx-signature>

        <cxx-returns><code>ostream_joiner&lt;decay_t&lt;DelimT&gt;, charT, traits&gt;(os, forward&lt;DelimT&gt;(delimiter));</code></cxx-returns>
      </cxx-function>
    </cxx-section>
  </cxx-section>
</cxx-clause>