help about pattern-matching

[Igor Medeiros <igorosbergster@...>]

Hi,

How to represent the pattern ([a-z]|[A-Z]|_)+([a-z]|[A-Z]|[0-9]_)* in Lua's format pattern.

I tried

patt = '([a-z]|[A-Z]|_)+([a-z]|[A-Z]|[0-9]_)*'

string.match( '_id', patt )

but the function match returned nil

 Thanks
Igor