A question: do you need to have the count per function or do you want to have an aggregate value (= how many times do all of the functions together appear in the source)?

In the first case you need to have some form of variable for each function-name to keep the tally (an array or --even better-- a hash will do the trick).

In the other case, you can build one big regex (all functions names joined together with | (which is "or" in a regex) and feed your source to that regex.

Warning: there can be many subtle traps and pitfalls:

• Make sure that no function is a substring of another function or you will count twice the shorter string (e.g. "print" and "printer; and if you have a function int your tally will be way off!".
• Variables who "contain" a function name will be counted as well if you're not careful (e.g. variable "lines_read" and function "read")
• ...