[polyml] Order of evaluation of arguments to a function

Is the following code supposed to print 1 followed by 2 or 2 followed by 1?

val _ = (fn () => (print "1\n"; fn x => x)) () (print "2\n"; ())

In SML/NJ, MLton and PolyML it does the former, while in Moscow ML it does the latter. Is this specified somewhere in the standard? I noticed equivalent code in OCaml behaves the way Moscow ML does which is not very surprising seeing how Moscow ML was based on Caml Light. Could this be a bug in Moscow ML?

The following code works the same in all 4 SML compilers (but different in OCaml):

val _ = (print "1\n"; 1) + (print "2\n"; 2)

It seems to me like SML/NJ, MLton and PolyML evaluate all function arguments left to right, OCaml evaluates them right to left, and Moscow ML seems inconsistent.