This post is part of the ClassicPress Plugin Development series in which I am going to look at both best practice for developing plugins and how I approach some requirements as well as some of the functions I commonly use.
Namespaces are a standard feature of PHP, post version 5.2. A namespace is a way of addressing the problem of isolation. For example, if you have a function called load_cs in one part of your code, then you cannot use the same name elsewhere. For ClassicPress this also means that having that function in one plugin, you cannot have the same name in another plugin.
To avoid this problem with ClassicPress, the common approach is to prefix function names (and class names) with a developer and plugin specific prefix; I typically use azrcrv_{nn}_ where the highlighted section is one to four letters to represent the specific plugin (e.g. e for Events, uam for Update Admin Menu or smtp for SMTP).
John Alarcon, Code Potent, uses namespaces in all of his plugins so does not need to use developer and plugin specific prefixes; instead he uses a developer and plugin name namespace. For example, the PHP Error Log Viewer uses the following namespace declaration:
// Declare the namespace.
namespace CodePotent\PhpErrorLogViewer;
I started developing plugins for WordPress (back in 2013) before namespaces were introduced to PHP and have never adopted them. I rewrote my WordPress plugins specifically for ClassicPress in 2019 after I migrated all of my sites, but did not adopt namespaces. Partly this was to maintain some backward compatibility as some of the plugins have functions which are intended to be called from outside the plugin (such as URL Shortener which is typically called to display the shortlink in a theme) and partly because at the time I didn’t especially see the benefit.
As time has passed and I’ve created more plugins, I am thinking that was a mistake and I should have introduced namespaces when I did the ClassicPress rewrite; if I make this change now to existing plugins, this would, under semver, be a breaking change necessitating a major version number increase.
If you are starting off developing for ClassicPress, I would encourage you to seriously consider using namespaces in your development of plugins.