Formal semantics of step expressions

Could someone please enlighten me what the result of the following "axis ... 
of ..." judgement should be?

axis child::  of
     element weight of type xs:integer {
       42 of type xs:integer
     }
  => ?

My intuition is that this should be text {"42"}. If this is so, could someone 
please point me to the part of the formal semantics where this conversion is 
defined?

Thanks,
--Stijn Vansummeren
University of Limburg
Belgium