[MLton-user] Posix.Process.exece on MinGW

[Dave Herman]

The MLton.World.load call uses Posix.Process.exece to restart the 
program with the special @MLton commands to load a world file, but in 
MinGW this isn't implemented.

I started trying to hack it in myself but ran up against my limited 
understanding of the MLton internals and the difficulty of hacking and 
recompiling the whole compiler (which takes a long time on my laptop).

I thought I'd report on my progress, and maybe Vesa or someone else can 
pick up where I left off.

I was trying to use the Win32 API functions documented here:

     http://msdn2.microsoft.com/en-us/library/20y988d2(VS.71).aspx

In basis-library/platform/mingw.sml, I added:

     val exece = PrimitiveFFI.MinGW.exece

and in runtime/gen/basis-ffi.def I added:

MinGW.exece = _import : NullString8.t * String8.t * C_Pointer.t array * 
C_Size.t vector * String8.t * C_Pointer.t array * C_Size.t vector -> 
C_Int.t C_Errno.t

and then in basis-library/posix/stub-mingw.sml I changed 
PrimitiveFFI.Process.exece to:

     val exece = if let open Primitive.MLton.Platform.OS in MinGW = host end
                 then MinGW.exece
                 else exece

Then in runtime/platform/mingw.c I added a new function:

C_Errno_t(C_Int_t) MinGW_exece (NullString8_t pNStr,
                                 String8_t aStr,
                                 Array(C_Pointer_t) aPtr,
                                 Vector(C_Size_t) aOff,
                                 String8_t eStr,
                                 Array(C_Pointer_t) ePtr,
                                 Vector(C_Size_t) eOff) {
     ...
}

I originally tried to implement this function as a shim for _execve in 
the Win32 API, and I tried copying the logic from 
runtime/basis/Posix/Process/exece.c, but there were issues with spaces 
in arguments.

At this point I'm so lost in the many layers of abstraction that I 
really don't know how all this fits together. :) Hopefully this is of use,

Thanks,
Dave