How to create regular expression to get all functions from code

Programming languages have a hierarchical structure, which means that they cannot be parsed by simple regular expressions in the general case. If you want to write correct code that always works, you need to use an LR-parser. If you simply want to apply a hack that will pick up most functions, use something like:

\w+\([^)]*\)

But keep in mind that this will fail in some cases. E.g. it cannot differentiate between a function definition (signature) and a function call, because it does not look at the context.

Change the * to + (if it exists in your regex implementation, otherwise do \w\w*). This will ensure that \w is matched one or more times (rather than the zero or more that you currently have).

It largely depends on the definition of "function name". For example, based on your description you only want to filter out the "empty"names, and not want to find all valid names.

If your current solution is largely enough, and you have problems with this empty names, then try to change the * to a +, requiring at least one word character right before the bracket.

\w+([^(]*)

OR

\w\w*([^(]*)

Depending on your regexp application's syntax.

(\w+)\(

regex groups would have the names of variables without any parentesis, you can add them later if you want, i supposed you don't need the parameters.

If you do need the parameters then use:

\w+\(.*\)

for a greedy regex (it would match nested functions calls)
or...

\w+\([^)]*\)

for a non-greedy regex (doesn't match nested function calls, will match only the inner one)