[omniORB] #include in .IDL file works incorrectly!!!

[Sai-Lai Lo]

David,

I guess what you are trying to do is something like this in pure OMG IDL.

// File     S.IDL
// OMG IDL
struct X {
  string A;
  char   B;
};


// File     MAIN.IDL
#include "S.IDL"

interface I {
   X op();
};


The complication is you want the definition of struct X to be done in a
single source file for both COM and CORBA.

1. Remember, the IDL compiler handle all the #include files only as IDL
   files so any C++ specific constructs in the files would not be
   recognised.

2. I suppose it is a bug that the compiler translate something like this:

     interface I {
     #include "S.IDL"
        X op();
     };

   into
     #include "S.hh"

     class I {
        ....
     };

   Hence relocate the #include out of the context it is used in the IDL.
   However, it is difficult to detect this and generate #include in the
   output at the right context.

3. I don't know if I have an answer to achieve what you want.
   One possibility may be to define a single IDL file with appropriate
   #if to separate OMG IDL specific and COM IDL specific part while
   sharing as much as possible. 

Regards,

Sai-Lai


>>>>> David Morgenlender writes:

> I'm trying to #include a .H file into my .IDL file.  But the IDL compiler is
> having problems:

> 1.  If I do the #include within an interface, I get a "can't parse statement"
> error & the compiler (omniidl2) crashes with a system exception.  

> 2.  So, for testing purposes, I moved the #include outside any interface & tried
> again.  I preceded the #include with a typedef statement, defining a type used
> by the .H file.  This compiled without error, but generated incorrect code, e.g.
> in the .HH file:

>   a.  The #include statement is put at the front of the .HH file, while the
> typedef is placed later, AFTER the #include, which requires it.

>   b.  The #include is for x.HH, when it should be for x.H.

> How can I get the IDL compiler to do what I need, which is handle a struct
> defined within an interface, via a .H file, placing a typedef before the struct?

> BTW, here's why I'm doing things this way ... I use the same struct in different
> apps, some of which use CORBA, some of which use COM, & some of which use both.
> The variables within the struct are carefully used so they generate compatible
> data for both CORBA & COM, assuming the typedef mentioned above is defined
> appropriately in both CORBA & COM .IDL files.  I desperately want to avoid
> having to define 2 different structs for CORBA & COM ... this is a very large
> struct!!!  

> So I'm #include'ing one .H into both my CORBA & COM IDL files.  I want to do
> this within an interface, so the struct typedef is essentially given a different
> name for CORBA than for COM, since one app will have both definitions.

> If the CORBA IDL compiler cannot be made to work with this approach, can you
> suggest something better???

> =======================================================
> Dave Morgenlender
> e-mail: dmorgen@alum.mit.edu
> =======================================================

-- 
Dr. Sai-Lai Lo                          |       Research Scientist
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E-mail:         S.Lo@orl.co.uk          |       Olivetti & Oracle Research Lab
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