B.3 Replace

This code is needed in the discussion of assignment in Assignment. where it serves as a solution to equation E0. The idea is that the function takes an argument of the form ((locations,values),store) and returns the store with the values stored at the locations indicated.

     
     locations = compose(left,compose(left,argument))
     values    = compose(right,compose(left,argument))
     store     = compose(right,argument)
     
     replace =
     
     refer conditional(
        store,
        (
           conditional(
              compose(left,locations),
              (
                 conditional(
                    compose(right,locations),
                    (
                       (hired meta)(
                          self,
                          couple(
                             (hired fan right)(locations,values),
                             (hired meta)(
                                self,
                                couple(
                                   (hired fan left)(locations,values),
                                   store)))),
                       couple(
                          (hired meta)(
                             self,
                             couple(
                                couple(compose(left,locations),values),
                                compose(left,store))),
                          compose(right,store)))),
                 conditional(
                    compose(right,locations),
                    (
                       couple(
                          compose(left,store),
                          (hired meta)(
                             self,
                             couple(
                                couple(compose(right,locations),values),
                                compose(right,store)))),
                       values)))),
              (hired meta)(
                 self,
                 couple(couple(locations,values),constant (nil,nil)))))