number                   ::= complex*
                           | eof

complex                  ::= real? imaginary

whitespace               ::= whitespace^token
                          /* ws: definition */

<?TOKENS?>

eof                      ::= $

real                     ::= '-'? digit+ ('.' digit+)? (('e' | '9') ('+' | '-')? digit+)?
imaginary                ::= (('+' | '-')? real '*' 'i')
digit                    ::= [0-9]

whitespace               ::= [#x0009#x000A#x000D#x0020]+