RE: [MI400] porting OS/400 compiler functionality to Windows...

["Steve Richter" <srichter@xxxxxxxxxxxxx>]

From: Don <dr2@cssas400.com>
>
> Have any of you folks considered porting a RPG or MI compiler to Window's
> MSIL?
>

Hi Don,

I think it would be an interesting discussion. The .NET CLR provides a way
to compile on the fly since the CLR is present on all .NET systems. Even
without the CLR, converting MI to windows or linux C code is at first glance
technically feasible.  The usrspc might be implemented as some sort of a
memory mapped file ( not sure of the sharing between processes
implications ) . A usridx could be implemented by a COM interface, where
behind the interface is an access database using the access run time
support. CALLX would be translated to a COM or DLL call. Even plain old rpg
database io could be handled by mimicing the action of the QDM* data mgmt
programs. Device IO would be a bit of work because you have to duplicate the
actions of the dds code in the device file. But it is still doable because
device io flows thru the QDM* program calls. Calls to qcmdexc would be
tough, but if you consider that 95% of qcmdexc calls are to run a limited
number of cl cmds like OVRDBF, CPYF, DLTF, CRTDTAARA,  then a functioning
command processor is not out of the question.

The show stopper though is IBMs closed source policy on its OS code. If that
code was open source and written in MI that code could be run through this
envisioned MI interpreter/translator.  But since it is not open source, the
many system calls that an RPG pgm makes behind the scenes would have to have
their functions duplicated, ... and that function is not documented.

Interesting idea though.

Steve