Sometimes I want to see all the constants I have defined. Here is some diagnostic PHP I use for displaying all user-defined constants.
Sometimes I want to see all the user-defined functions that are in memory when a page loads. Maybe the page doesn’t need certain functions and I can realize performance improvements by removing them. And sometimes — I’m being candid here — I copy functions from one application into a library file for another and don’t need any of them for the current application. This function, offering some diagnostic PHP, helps.
Sometimes when developing, it’s helpful to echo some diagnostic information to the screen. Here’s some simple diagnostic PHP I use for displaying all included files.