Replaced all but one occurrence of perm_simp_tac by perm_simproc_app,
since perm_simp_tac now behaves in a different way (due to changes
in swap_simps).
structure ROOT =
struct
structure Codegen =
struct
fun lookup ((k, v) :: xs) l =
(if ((k : string) = l) then SOME v else lookup xs l)
| lookup [] l = NONE;
end; (*struct Codegen*)
end; (*struct ROOT*)