Vim and function completion - how?

With PHP, I can have a file with all the functions list in it, and in my .vimrc, I can add the following:

set dictionary-=~/.funclist.txt dictionary+=~/.funclist.txt
set complete-=k complete+=k

Where .funclist.txt contains all the list of PHP functions. Typing CTRL-N (and CTRL-P to reverse the completion) in edit mode will enable auto completion. Sweet.

Now, in my development work, I write a lot of functions (or methods, depending on what hat you're wearing). Question is, in order to use auto completion, I have to manually add my function names to .funclist.txt. I'm resorting to a Perl script that will scan my development directory (usually it is just a particular directory) for functions, compare it to a list I have, and add them to the list if they're new.

Is there a better way to do this?