The SOMobjects Toolkit offers a more flexible approach to managing interface repositories. The SOMIR environment variable can reference an ordered list of separate IR files, which process from left to right. Taken as a whole, however, this gives the appearance of a single, logical interface repository. A programmer accessing the contents of "the interface repository" through the SOM Interface Repository framework would not be aware of the division of information across separate files. It would seem as though all of the objects resided in a single interface repository file.
A typical way to utilize this capability is as follows:
Developers working on different projects would each set their SOMIR environment variables to hold slightly different lists. For the most part, the leftmost portions of these lists would be the same, but the rightmost interface repositories would differ. When any given developer is ready to share his/her interface definitions with other people outside of the immediate work group, that person's interface repository can be promoted to inclusion in the master list.
With this arrangement of IR files, the more stable repositories are found at the left end of the list. For example, a developer should never need to make any significant changes to "som.ir", because these interfaces are defined by IBM and would only change with a new release of the SOMobjects Toolkit.
The Interface Repository Framework only permits updates in the rightmost file of the SOMIR interface repository list. That is, when the SOM Compiler -u flag is used to update the Interface Repository, only the final file on the IR list will be affected. The information in all preceding interface repository files is treated as "read only". Therefore, to change the definition of an interface in one of the more global interface repository files, a developer must overtly construct a special SOMIR list that omits all subsequent (that is, further to the right) interface repository files, or else petition the owner of that interface to make the change.
It is important the the rightmost filename in the SOMIR interface repository list not appear elsewhere in the list. For Example, the following setting for SOMIR:
%SOMBASE5\ETC\SOM.IR;SOM.IR;C:\IR\COMPANY.IR;SOM.IR
would cause problems when attempting to update the SOM.IR file, because SOM.IR appears twice in the list.
Here is an example that illustrates the use of multiple IR files with the SOMIR environment variable. In this example, the SOMBASE environment variable represents the directory in which the SOMobjects Toolkit files have been installed. Only the "myown.ir" interface repository file will be updated with the interfaces found in files "myclass1.idl", "myclass2.idl", and "myclass3.idl".
For OS/2:
set BASE_IRLIST=%SOMBASE%\IR\SOM.IR;C:\IR\COMPANY.IR;C:\IR\DEPT10.IR set SOMIR=%BASE_IRLIST%;D:\MYOWN.IR set SMINCLUDE=.;%SOMBASE%\INCLUDE;C:\COMPANY\INCLUDE;C:\DEPT10\INCLUDE sc -usir myclass1 sc -usir myclass2 sc -usir myclass3
For AIX:
export BASE_IRLIST=$SOMBASE/ir/som.ir:/usr/local/ir/comany.ir:\
/usr/local/ir/dept10.ir
export SOMIR=$BASE_IRLIST:~/myown.ir
export SMINCLUDE=.:$SOMBASE/INCLUDE:/usr/local/company/include:\
/usr/local/dept10/include
sc -usir myclass1
sc -usir myclass2
sc -usir myclass3