[MLton] Monadic MLton.Vector.create

[Henry Cejtin]

No,  I  don't believe that monads are powerful enough in a language with side
effects.  The function that is passed update can put it in a ref cell.

I was thinking of the older style for I/O in purely functional languages: you
have  to have a the functions return to their callers, passing both what they
want done (sub or update) and also a continuation.  Using that,  and  in  the
absence  of  call/cc, the create function could be certain that update wasn't
called after it returns.

I would say that the result is pretty ugly because of the need to pretty much
handle the continuations by hand in the tabulator and whacker functions.