Identifying Functionality and Output

Actions and filters hook our functions to WordPress plugin API commands. By now, you should have an understanding of how this works and how it looks in a plugin file. In generic terms, WordPress plugins have two distinct purposes:

• Functions: Defined within the plugin code through a combination of actions and hooks; essentially, functions define what the plugin does.
• Output: What is displayed on your site as a result of the plugin function(s). For example, if the plugin function(s) makes calls to the database to retrieve a certain type of post (for instance, from a certain category or tag) from your content, the output is how those posts then get displayed on your site for your readers to see. Plugins can also use HTML markup and CSS to provide basic styling for the output.