Regular Expressions in CoffeeScript are Awesome(elijahmanor.com)

  my $emailPattern = qr{ ^ #begin of line
   ([a-z0-9_.-]+)          #one or more letters, numbers, _ . or -
   @                       #followed by an @ sign
   ([\da-z.-]+)            #then one or more letters, numbers, _ . or -
   \.                      #followed by a period
   ([a-z.]{2,6})           #followed by 2 to 6 letters or periods
   $ }xi;                  #end of line and ignore case

  if( '[email protected]' =~ $emailPattern ){
     print "E-mail is valid\n";
  } else {
     print "E-mail is invalid\n";
  }

  use Mail::Sendmail;
  if( '[email protected]' =~ /$Mail::Sendmail::address_rx/ ){
     print "E-mail is valid\n";
  } else {
     print "E-mail is invalid\n";
  }

  var foo = new RegExp(
                    '\\d\+' + // First digit
                    '-' +     // Delimiter
                    '\\d\+'   // Second digit
                    );
  foo.test("1234-5432");

  a = re.compile(r"""\d +  # the integral part
                   \.    # the decimal point
                   \d *  # some fractional digits""", re.X)
  b = re.compile(r"\d+\.\d*")