semiring_numeral_0_eq_0, semiring_numeral_1_eq_1 now [simp], superseeding corresponding simp rules on type nat; attribute code_abbrev superseedes code_unfold_post
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*)