[MLton] FFI types

[Henry Cejtin]

I  can  see  the  problem  with the cast being from string to MLton.Pointer.t
because of a GC.  I would think that still, some kind of primitive  would  do
the  job.   What  currently is the mechanism which goes from a string to what
actually gets passed to the C code (to make the types right)?

The point is that a pointer in C really IS an xxx option in ML.  It is such a
common idiom in C code that you really want the FFI to understand it.