Validate correctness of a regular expression - Ruby/Ruby on Rails

Question

Let's say I got a regular expression like this:

/\b[A-Z0-9._%a-zöäüÖÄÜ\-]+@(?:[A-Z0-9a-zöüäÖÜÄ\-]+\.)+[A-Za-z]{2,4}\z/

How can I check via Ruby/RoR if this string is a valid regular expression?

Answer 1

If it doesn't raise errors, it's a valid regex. :)

def valid_regex?(str)
  Regexp.new(str)
  true
rescue
  false
end

valid_regex?('[a-b]') # => true
valid_regex?('[[a-b]') # => false