PHP - acnorrisuk/coding-style-guide GitHub Wiki

Single quotes should be used for strings unless you're making use of double quotes to parse a string with variables in it.

You are free to use PHPs alternative control structure (i.e. endif, endwhile) syntax if it helps readability.

Similarly, you can choose to output HTML in whichever way affords the most readability.

<!-- Using single PHP quotes -->
<?php echo '<a href="' . $link . '" class="' . $class . '">Link</a>'?>

<!-- Using double PHP quotes (although this does lead to single quotes in HTML attributes) -->
<?php echo "<a href='$link' class='$class'>Link</a>"?>

<!-- Using printf() -->
<?php printf("<a href='%s' class='%s'>Link</a>", $link, $class);?>

<!-- Using PHP tags -->
<a href="<?php echo $link;?>" class="<?php echo $class;?>">Link</a>

Never use shorthand php tags as this could break compatibility with other languages (e.g. XML)

<!-- Avoid -->
<? ?>
<?= ?>

<!-- Better -->
<?php ?>

Omit the final PHP tag if it closes the document as this helps prevent errors involving extra whitespace.

Capitalise SQL queries to help readability

Use snake_case for naming variables

Lean towards readability in logic rather than cleverness

// A little confusing
isset( $var ) || $var = some_function();

// Clearer
if ( ! isset( $var ) ) {
    $var = some_function();
}