Question

I am trying to write a regular expression for the following scenario.

It could be simple alphanumeric string (It can have ‘@’ even if it is special character) or alphanumeric string followed by argument list in parenthesis or alphanumeric string followed by blank parenthesis:

1. My_macro -> accept this
2. My_macro() -> accept this
3. My_macro(arg1, arg2, arg3) -> accept this

I am new to regular expression, I read some tutorials and could form this regular expression.

([a-zA-Z]+[a-zA-Z0-9_@]*) | ([a-zA-Z]+[a-zA-Z0-9_@.]+[\(][a-zA-Z]+[a-zA-Z0-9_@,]+[\)])

This isn’t working.

Answer 1

^[\w@]+(\((\w+,?\s*)*\))?$

matches:

My_macro(arg1,  arg2, arg3)
My_macro(arg1)
My_macro
My_macro()
My_macro@()

^                   # Line Start
[\w@]+              # Matches alphanumerics and @ => My_@macro
(\((\w+,?\s*)*\))?  # Matches optional argument (empty) list (), (arg) and (arg1, arg2) 
$                   # Matches Line End  

The question is what exactly are you trying to achieve. Why do you need to match these strings? Your requirements matches most strings anyways.