[wp-hackers] apply_filters() in an if statement?

[Nathan Rice]

It's an easy way for a plugin to change the outcome of an if() check.

For instance, if I wanted to display a banner above my header, I could do
this:

if ( apply_filters( 'show_banner_above_header', '' ) )
  show_banner_above_header();

or, I would more likely do this:

if ( apply_filters( 'show_banner_above_header', false ) )
  show_banner_above_header();

... then a plugin could come along and do this:

add_filter( 'show_banner_above_header', '__return_true' );

... and the banner would then show.

Of course, you could reverse the whole things and use __return_false as the
callback for add_filter() and get the opposite result.

------------------
Nathan Rice
WordPress and Web Development
www.nathanrice.net | twitter.com/nathanrice


On Wed, Feb 29, 2012 at 3:38 PM, Micky Hulse <mickyhulse.lists at gmail.com>wrote:

> Hello,
>
> Sorry in advance if this type of question belongs on the forums...
>
> I am hacking a theme, and they have something like this (abbreviated):
>
> [code]
>
> if (option('foo') || apply_filters('baz_baz', '') ||
> apply_filters('bar_bar', '')) {
>
>   $bar_bar = apply_filters('bar_bar', blah, blah);
>   $return = apply_filters('baz_baz', blah, blah);
>
> }
>
> [/code]
>
> What does apply_filters('string', '') accomplish? I guess I am
> confused because the second argument is an empty string.
>
> This helps to explain (at least in my brain) what apply_filters() does:
>
> "In the most basic terms, apply_filters is used to initialise a filter
> hook... add_filter assigns a new function to hooks that have already
> been created."
> --<
> http://stackoverflow.com/questions/2270989/what-does-apply-filters-actually-do-in-wordpress
> >
>
> But why would you put it in an if statement with an empty string for
> the second argument?
>
> Am I talking crazy here?
>
> Let me know if this type of question is too noob for this list. I
> don't want to bug folks with simple ones. :D
>
> Thanks a billion!
>
> Cheers,
> Micky
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