Trouble understanding apply_filters()

  • In apply_filters()

    apply_filters( $tag, $value, $var ... )

    I’m having trouble wrapping my head around the $value and $var. I read the codex and it sounds like the $value can be modified, $var not, but I haven’t found any examples of this in the wild. It seems to be used as a way to pass a variable. In which case, what’s the difference between that and the $var? ?

    Thanks

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  • Thread Starter Jack Reichert

    (@jackreichert)

    Thanks.

    I got a great response on wordpress.Stackexchange.com.

    Quoted:

    Try to see the function with names:

    apply_filters( $filter_name, $value_to_change, $extra_information_1, $extra_information_2 );
    So when that function is called as:

    // wp-login.php line 94
    apply_filters( 'login_body_class', $classes, $action );
    You can use …

    add_filter( 'login_body_class', 'function_to_change_login_body_class', 10, 2 );
    … and get two variables passed to that function. You can return just the first, the second provides just more context:

    function function_to_change_login_body_class( $classes, $action )
{
    if ( 'login' === $action )
        $classes[] = 'foo';

    if ( 'postpass' === $action )
        $classes[] = 'bar';

    return $classes;
}

    The additional variables are there to make your decisions easier, not to change those too.

Viewing 1 replies (of 1 total)
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