non-critical output primitives -- depending on thread-safe TextIO, while races wrt. flushing should not matter;
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*)