Dougal Campbell

The Text Filter Suite (“TFS”, hereafter) is a WordPress plugin which 
adds some new text filtering functions. In a sense, the core TFS 
functions could be considered a “meta filter”, because they actually 
provide a framework that let you construct new filters fairly easily. 
They also provide an easy way to apply filters to post content and 
comments on a per-post basis.
<h4>Huh? Can you repeat that in English?</h4>
Okay, let’s try a real-world example. A common feature on many web 
sites is the automatic handling of acronyms. You’ll often see an 
acronym such as “XHTML” displayed in an alternate style, and when you 
hover your mouse pointer over it, you get a tool-tip which displays the 
definition (“eXtended HyperText Markup Language”, in this case). You 
don’t want to have to type in the markup for this every time you post 
something, and automation is what computers are for, right? So, there 
are several plugins available to handle this sort of automated text 
subsitution.
TFS comes with the “TFS Acronymit” plugin to perform this function. 
It’s based on Matt Mullenweg’s original “Acronymit” function, but with 
a couple of improvements. In Matt’s original function, you had to keep 
the acronym list sorted, longest-to-shortest, and it could get confused 
by recursive acronyms like ‘PHP’ (“PHP Hyptertext Processor”) or GNU 
(“GNU’s Not Unix”). TFS Acronymit does not have those restrictions.
For those who think that expansion of technical acronyms is “teh sux0r” 
(i.e. “boring”), TFS comes with a variety of more entertaining filters. 
The current set includes “chef”, “fudd”, “jive”, “kraut”, “pirate”, and 
of course, the aforementioned “acronymit”. As a word of caution, the 
“jive” and “kraut” filters are not what you would call “politically 
correct”. 
By default, if the “TFS Pirate” filter is active, it will automatically 
apply itself to all content on Talk Like a Pirate Day (September 19). 
If you do not want this filter to automatically activate, set the value 
of the “$talk_like_a_pirate” variable at the top of the plugin source 
to “false”.
The “TFS Acronymit” filter is automatically applied to all posts 
whenever it is active. You do not need to set special post custom 
fields in order to use it. Just activate the plugin, and you’re ready. 
To modify which acronyms are defined, see the list at the beginning of 
the plugin, and modify it as you like, following the format you see 
there.
It is possible to use the TFS core without activating any additional 
plugins. You can do this with any built-in PHP function accepts a 
single string as a parameter and returns a string. For example, you 
could set a post custom “content_filter” with the value “strrev”, and 
the contents of the post would be displayed backwards, or with a value 
of “strtoupper” to convert the content to all uppercase text.
You can only specify a single function in each post custom field. 
However, you can chain multiple functions together by using the key 
more than once. For instance, if you wanted all comments for a post to 
display in uppercase Elmer Fudd text, you would set two post custom 
fields:
comment_filter = strtoupper 
 comment_filter = fudd
HOWEVER, note that using PHP built-in functions in this way will bypass 
the power of the filter_cdata_content() function, which means that it 
can and will mangle your HTML tags, possibly rendering them useless. 
For example, applying the strrev function to the string “
<
p>” will 
transform it into “>p<“, which will confuse your browser in new and 
wonderful ways.
NOTE: These filters can be very CPU intensive. For one thing, they make 
extensive use of regular expressions, which can be expensive on their own. 
And for another, they break your content into many small chunks, in order to 
separate the filterable text from the HTML code, and the filters run 
separately on each text chunk found. This probably won’t be a problem in 
most cases. But if you have long posts being filtered, and you get a lot of 
traffic, it could start to add up. A caching plugin (e.g., WP Super Cache, 
or W3 Total Cache) would probably help in that case.
<h3>The Future</h3>
I will one day release a version 2.0 of this plugin which will be completely 
refactored. You can probably expect to see: 
* Consolidate the code so that it is not a collection of separately-enabled 
 mini-plugins. 
* PHP5 OOP architecture to encapsulate everything. 
* An actual admin interface to select which filters are enabled, which 
 bits of content you will allow to be filtered (post titles, post content, comments, 
 blog title, widget titles, etc), whether to auto-activate the Pirate 
 filter on Talk Like a Pirate Day, etc.
Eventually, there may also be a way to edit the string substitutions so that 
you can tailor it to your tastes.
<h3>Credits</h3>
I created TFS on my own, but I borrowed ideas from several sources. Here are 
some links you might also want to check out:
<pre><code>PhotoMatt's original Acronymit code:
 http://photomatt.net/scripts/acronymit

Simon Willison and I traded some ideas when I started my original hack
for Talk Like a Pirate Day, in 2003:
 http://simon.incutio.com/archive/2003/09/19/aaar

I borrowed, modified, and mangled a ton of stuff from Adam Kalsey's
"MovableJive" plugin for Movable Type. See tfs-jive, tfs-chef, tfs-fudd,
and tfs-kraut.
 http://kalsey.com/2003/02/movablejive/

If all you want to do is stuff like the acronym definitions (or similar
"turn this shorthand into a tag" substitions), then Michel Valdrighi's
"Tag, You're It" plugin is really a better solution:
 http://zengun.org/weblog/archives/2004/05/tag-you-re-it

The original inspiration that led to TFS was my desire to apply a
"pirate" filter on my blog for "Talk Like a Pirate Day", which is on
September 19 of each year:
 http://talklikeapirate.com/
</code></pre>

Text Filter Suite

Advanced filtering functions for WordPress, including the Talk Like a Pirate Day filters.

Jason Stallings

This plugin plays an air horn when you login, and adds an air horn button to the WordPress toolbar.
Usage:
Login and hear the Air Horn!

Text Filter Suite vs Air Horn