a

local MyMap L Lout A B1 B2 C F in
   MyMap = proc {$ Xs F R}
      case Xs
      of nil then
        R = nil
      [] X|Xr then
        local T A in
            {F X A}
            {MyMap Xr F T}
            R = A|T
        end
      end
   end

   L = [1 2 3 4]
   F = proc {$ X R}
        R=X*X
    end

   {MyMap L F Lout}
   A = Lout.1
   B1 = Lout.2
   B2 = B1.1
   C = A + B2
   {Browse C}
end