xmlns = "http://studentsRus.org/"

Name   = [a-zA-Z]+(\ [a-zA-Z]+)*
Email  = [a-zA-Z._]+\@[a-zA-Z._]+
Id     = [0-9]{8}
NL     = \r\n|\r|\n

file : [persons p] = <students> [persons p] </>

persons : [person p] [NL] [persons more] = [person p] [persons more]
        : =

person : [Name name] __ "(" [Email email] ")" _ [Id id] = 
         <student sid=[Id id]>
             <name> [Name name] </> 
             <email> [Email email] </> 
         </>