The Loop

The Loop consists of PHP and HTML code that gets and displays posts for a page. The Loop is a key component of a WordPress theme.

Code 2. The Loop's Basic Code

<?php if (have_posts()) : ?>  <?php while (have_posts()) : the_post(); ?>    <?php the_content(); ?>  <?php endwhile; ?> <?php endif; ?>

Loop basics

When broken down to its simplest form (Code 2), The Loop is actually quite simple:

<?php if (have_posts()) : ?>

This starts by querying the database to determine whether there are posts to display. If there are, the next commands are executed; if not, WordPress skips ahead to the end of The Loop.

<?php while (have_posts()) :  the_post(); ?>

This line of code tells WordPress to get post information. It starts The Loop's actual loopa collection of code that is repeated for each item. In this case, the code inside the loop is repeated for each post. The actual number of posts it is repeated for is determined by WordPress settings, as discussed in Chapter 2.

<?php the_content(); ?>

This line tells WordPress to display the contents of the post.

<?php endwhile; ?>

This closes the loop when the specified number of posts have been retrieved and displayed.

<?php endif; ?>

This is the end of The Loop.

Beyond the Basics

Of course, Code 2 is an extremely basic example. Although it will work in an index.php file as istry it and see for yourself!it omits much of the information readers expect to see, such as the post title, the post author, the post date, and so on. To add this information, insert the appropriate tags between the second and fourth line of this example.

Tips

• Anything inside The Loop will appear with every post. For example, you may wish to add a small image to each post to mark a special event such as Christmas. If you add it inside the loop the image will appear once with each post. If you add it outside the loop it will appear once for the whole page.

• Some template tags can only be used in The Loop. That's because those tags retrieve and display information that is specific to a post, such as the author's name or the post date and time.

The Loop in the Default theme

In the Default theme, The Loop is much more complex. Code 3 on the next page shows the code required by The Loop in black and additional content and formatting code in gray.

As you can see, this version of The Loop includes far more template tags. It also calls on other worker files, with their own template tags, that are part of the theme. All these tags send requests to the database and display the results that include the post title, the author name, the post date, and comment links (Figure 1). If there is nothing to display, WordPress tells you and displays a Search form (Figure 8).

Figure 8. The Default theme displays a Search form if there are no posts to display.

The post in The Loop

The contents of the blog post itself is represented by one single line of code within The Loop.

In Code 2, it's <?php the_content(); ?>, which simply displays the post content.

In Code 3, from the Default theme, it's <?php the_content('Read the rest of this entry &raquo;'); ?>. This includes instructions to create a link to any part of the post that follows a special <!--more--> tag inserted by the post author within the post. The wording of the link is: Read the rest of this entry ».

Code 3. The Loop in the Default theme's index.php file

<?php if (have_posts()) : ?>  <?php while (have_posts()) : the_post(); ?>    <div  >      <h2><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to      <?php the_title(); ?>"><?php the_title(); ?></a></h2>      <small><?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> --></small>      <div >        <?php the_content('Read the rest of this entry &raquo;'); ?>      </div>      <p >Posted in <?php the_category(', ') ?> |      <?php edit_post_link('Edit', '', ' | '); ?> <?php comments_popup_link('No Comments      &#187;', '1 Comment &#187;', '% Comments &#187;'); ?></p>    </div>  <?php endwhile; ?>  <div >    <div ><?php next_posts_link('&laquo; Previous Entries') ?></div>    <div ><?php previous_posts_link('Next Entries &raquo;') ?></div>  </div> <?php else : ?>  <h2 >Not Found</h2>  <p >Sorry, but you are looking for something that isn't here.</p>  <?php include (TEMPLATEPATH . "/searchform.php"); ?> <?php endif; ?>