[jhc] dynamic library support?

[Mark Wotton]

On 06/08/2009, at 6:11 PM, John Meacham wrote:

> On Thu, Aug 06, 2009 at 05:22:06PM +1000, Mark Wotton wrote:
>> Is there a way to build dynamic libraries in jhc such they're  
>> linkable
>> and callable from a C driver?
>> I'm hoping to write a bridge between ruby and haskell, and GHC's  
>> dynamic
>> lib support seems a bit sketchy currently.
>
> If your interface is constrained to things expressible in the FFI  
> spec,
> then you can 'foreign export' whatever functions you like from haskell
> then compile the resulting C file into a shared library. I don't  
> have a
> specific option that does this automatically, but it should be easy to
> do by hand once you see the C file it produces. Let me know what  
> issues
> you run into, if we can come up with a generally useful 'recipe' for
> creating shared libraries from haskell I'd like to add it as an  
> explicit
> command line option to jhc.

Colour me shocked, if I just comment out the main function, the  
exported functions work fine.
Thanks, this is really helpful. I'd like to see if other packages work  
as well - how do you enable extra libraries like containers?
jhc --list-libraries shows that containers-0.2.0 is there, but when i  
try to compile a program with Data.Map calls in it, jhc complains  
bitterly:

mwotton at ubuntu-vm:/mnt/hgfs/projects/rhaskell/linux$ jhc -v Test.hs
reading /usr/local/etc/jhc-0.6/targets.ini
reading /usr/local/etc/jhc-0.6/targets.ini
jhc -v Test.hs
jhc 0.6.1 (0.6.0-32)
Compiling [Right "Test.hs"]
Loading libraries: ["base","haskell98"]
Library: base-1.0        </usr/local/share/jhc-0.6/base-1.0.hl>
Library: haskell98-1.0   </usr/local/share/jhc-0.6/haskell98-1.0.hl>
Test.hs:1   - Warning: The pragma 'LANGUAGE' is unknown
Main                    [Test.hs] <Test.ho>
Error: Module not found: Data.Map

Thanks once again, I might actually get this project out the door  
soonish.

Cheers
Mark