The IDL compiler is capable of accepting a couple of IDL variants as input, with the following options controlling which one it should expect:
-fdce
Tell the compiler to accept OSF's DCE IDL syntax. The conformance to DCE IDL isn't alltogether strict, in that the couple of minor extensions that HaskellDirect makes will still be recognised.
-fcom
Instruct the IDL compiler to accept the language used by the Microsoft IDL compiler, a superset of DCE IDL (extended to support the description of COM interfaces.)
This option also has ramifications for what kind of stub code is generated, see next section.
-fomg
This option enables a front-end that accepts the OMG CORBA IDL syntax instead of DCE IDL. This front-end is currently experimental, but should be of some use if you intend to use HaskellDirect and OMG IDL to describe bindings to C libraries (see below).
Please notice that HaskellDirect does not currently ship with a backend and support library that allows you to interface to any CORBA-compliant ORBs.
-cpp
Instruct the compiler to initially run the C preprocessor over the input. See Section Running a pre-processor for details.
The default is to accept the IDL that the Microsoft IDL compiler
recognises, i.e., -fcom.