Queue

declare

fun {Append L V}
   case L of
      nil then [V]
   [] X|Xr then
      X|{Append Xr V}
   end
end




class Cola\4
   attr
      L
   meth inic
      L:=nil
   end

   meth push(Val)
      L:={Append @L Val}
   end

   meth pop(?Val)
      case @L of
     nil then Val=nil
      [] X|Xr then
     Val=X
     L:=Xr
      end
   end


   meth browse
      {Browse @L}
   end


end

declare C={New Cola inic}
{C push(1)}
{C push(2)}
{C push(3)}
{C browse}

local A B in
{C pop(A)}
   {C browse}
   {C pop(B)}
{C browse}
   {Browse A#B}
end