Where the view rendering logic belongs to, functions.php or content-partial template?

I am implementing a “Recently Post” rendering logic with WordPress recently. Based on @helenhousandi’s example, I did the task through WP_Query() to pull out my posts.

However, I am facing a architecture issue right now. In WordPress, there are 3 ways to include this loop rendering snippets inside a single.php file:

---

1. Put the rendering logic directly in single.php

single.php

<div id="header-announcements">
<h3>Announcements</h3>
    <?php
    $queryObject = new WP_Query( 'post_type=announcements&posts_per_page=5' );
    // The Loop!
    if ($queryObject->have_posts()) {
        ?>
        <ul>
        <?php
        while ($queryObject->have_posts()) {
            $queryObject->the_post();
            ?>

            <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
        <?php
        }
        ?>
        </ul>
        <div><a href="#">View More</a></div>
        <?php
    }
    ?>
</div>

This is the easiest way, but hard to reuse for other custom post type.

---

2. Using get_template_url() to include the loop rendering logic

conctent-recently-post.php

<?php
$queryObject = new WP_Query( 'post_type=announcements&posts_per_page=5' );
// The Loop!
if ($queryObject->have_posts()) {
    ?>
    <ul>
    <?php
    while ($queryObject->have_posts()) {
        $queryObject->the_post();
        ?>

        <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
    <?php
    }
    ?>
    </ul>
    <div><a href="#">View More</a></div>
    <?php
}
?>

single.php

<div id="header-announcements">
<h3>Announcements</h3>
    <?php get_template_url( 'content', 'recently-post'); ?>
</div>

Put the rendering logic in a separate template file, say content-recently-post.php, and then include that in single.php. This should be better, since it could be reused in other template files.

What fall short here is that, the post_type and posts_per_page are tightly coupled with the rendering logic, so it’s still hard to reuse.

---

3. Register a function in functions.php, and call the function in single.php

functions.php

<?php
if(!function_exists('ka_show_recently_post')) :
    function ka_show_recently_post($post_type, $num) {
      $queryObject = new WP_Query( 'post_type=' . $post_type . '&posts_per_page=' . $num );
      if ($queryObject->have_posts()) :
          echo '<ul>';
          while ($queryObject->have_posts()) :
              $queryObject->the_post();
              echo '<li><a href="' . get_the_permalink() . '">' . get_the_title() . '</a></li>';
          endwhile;
          echo '</ul>';
      endif;
    }
endif;
?>

single.php

<div id="header-announcements">
<h3>Announcements</h3>
    <?php ka_show_recently_post('announcements', 5) ?>
</div>

The good part for this approach is that it allows you to reuse it according to the post_type and posts_per_page that you would like to, but I think it’s a little weird to put these kinds of rendering logic in functions.php. We should put all these template relating logic in separate template files, which forms a better structure for future maintenance, shouldn’t we?

I am wondering is there any other better ways to solve the rendering
logic in WordPress like that in this example?