RosettaCodeData/Task/Catamorphism/Refal/catamorphism.refal

$ENTRY Go {
    , 1 2 3 4 5 6 7: e.List
    = <Prout <Reduce Add e.List>>
      <Prout <Reduce Mul e.List>>;
};

Reduce {
    s.F t.I = t.I;
    s.F t.I t.J e.X = <Reduce s.F <Mu s.F t.I t.J> e.X>;
};