Does function definition order matter?

Question

In the script below, does the order in which items are declared matter?

For example, if the add_action points to a function that has not yet been defined? Does it ma

Answer 1

No.
It is not C :P...
As you can see here , the whole file is first being parsed and then executed.
If a function that doesn't exist is being called, php will throw an error.

Fatal error: Call to undefined function