RE: Re[2]: How to find out the C type signature corresponding to a Haskell function type in FFI?
On 09 March 2006 16:39, Bulat Ziganshin wrote: Hello Simon, Thursday, March 9, 2006, 5:08:09 PM, you wrote: for small home projects you can even use Int and int which would work in most of Haskell implementations Yes, and to give a concrete example: HsInt and int are different types on x86_64 (and most other 64-bit C implementations). yes, it's better to use Int and long types :) I hope that smiley means you're joking... Cheers, Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re[2]: How to find out the C type signature corresponding to a Haskell function type in FFI?
Hello Marcin, Thursday, March 9, 2006, 2:20:00 AM, you wrote: foreign import ccall duma_init :: Int - IO Int MQK HsInt duma_init(HsInt arg); MQK Or use int on the C side and CInt on the Haskell side. MQK fromIntegral can be used for converting integers in Haskell. for small home projects you can even use Int and int which would work in most of Haskell implementations -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
Am Donnerstag, 9. März 2006 08:46 schrieb Bulat Ziganshin: Thursday, March 9, 2006, 2:20:00 AM, you wrote: foreign import ccall duma_init :: Int - IO Int MQK HsInt duma_init(HsInt arg); MQK Or use int on the C side and CInt on the Haskell side. MQK fromIntegral can be used for converting integers in Haskell. for small home projects you can even use Int and int which would work in most of Haskell implementations Uh, oh... :-( This is roughly as safe as assuming that short, int, long, and long long are of the same size, so this is highly discouraged. The rationale behind the FFI addendum is as follows: * If you want to use a given C API, use the types from Foreign.C.Types on the Haskell side in the foreign imports. * If the C API is under your control, you have basically two options: Either use Foreign.C.Types as above, or use the types/preprocessor #defines in the HsFFI.h header to bind to basic Haskell types. Which option is better suited depends on what you are trying to achieve. This should be easy enough to use and everything else is not guaranteed to work... Cheers, S. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
Sven Panne wrote: Am Donnerstag, 9. März 2006 08:46 schrieb Bulat Ziganshin: Thursday, March 9, 2006, 2:20:00 AM, you wrote: foreign import ccall duma_init :: Int - IO Int MQK HsInt duma_init(HsInt arg); MQK Or use int on the C side and CInt on the Haskell side. MQK fromIntegral can be used for converting integers in Haskell. for small home projects you can even use Int and int which would work in most of Haskell implementations Uh, oh... :-( This is roughly as safe as assuming that short, int, long, and long long are of the same size, so this is highly discouraged. The rationale behind the FFI addendum is as follows: * If you want to use a given C API, use the types from Foreign.C.Types on the Haskell side in the foreign imports. * If the C API is under your control, you have basically two options: Either use Foreign.C.Types as above, or use the types/preprocessor #defines in the HsFFI.h header to bind to basic Haskell types. Which option is better suited depends on what you are trying to achieve. This should be easy enough to use and everything else is not guaranteed to work... Yes, and to give a concrete example: HsInt and int are different types on x86_64 (and most other 64-bit C implementations). Cheers, Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re[2]: How to find out the C type signature corresponding to a Haskell function type in FFI?
Hello Brian, Wednesday, March 8, 2006, 12:03:27 AM, you wrote: BH mycallback :: GUIMonad m = EventInfo - m EventResult BH 'm' will have to combine a state monad with the IO monad (so I can use IORef BH etc if needed). as Ian Lynagh wrote, it's no problem if your monad is IO-based. if FFI by itself don't support this, you can add liftIO wrappers: foreign import f :: IO () f_wrapper :: GUIMonad m = m () f_wrapper = liftIO f -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
Brian Hulley [EMAIL PROTECTED] writes: I've got a Haskell module with the following ffi import: foreign import ccall duma_init :: Int - IO Int However my problem is that I've got no idea what the type signature for the corresponding C function should be, HsInt duma_init(HsInt arg); Or use int on the C side and CInt on the Haskell side. fromIntegral can be used for converting integers in Haskell. -- __( Marcin Kowalczyk \__/ [EMAIL PROTECTED] ^^ http://qrnik.knm.org.pl/~qrczak/ ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
How to find out the C type signature corresponding to a Haskell function type in FFI?
Hi - I've got a Haskell module with the following ffi import: foreign import ccall duma_init :: Int - IO Int However my problem is that I've got no idea what the type signature for the corresponding C function should be, and when I compile the above module with ghc -fglasgow-exts -fffi --make it doesn't create any stubs either. I've tried looking at the wiki but that only seems to give specific examples. I'm trying to find what the mapping is between Haskell function signatures and C signatures is in general. Any ideas? Also, I really wanted to be able to use () - IO () but () doesn't seem to be allowed in FFI... A third point is, how would I pass an arbitrary monad instead of just using IO? Thanks, Brian. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
Hello Brian, Tuesday, March 7, 2006, 7:35:27 PM, you wrote: BH foreign import ccall duma_init :: Int - IO Int int duma_init(int); BH I've tried looking at the wiki but that only seems to give specific BH examples. I'm trying to find what the mapping is between Haskell function BH signatures and C signatures is in general. Any ideas? see official FFI documentation - http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi.pdf and excellent paper Tackling the awkward squad: monadic input/output, concurrency, exceptions, and foreign-language calls in Haskell (http://research.microsoft.com/Users/simonpj/papers/marktoberdorf/marktoberdorf.ps.gz) BH Also, I really wanted to be able to use () - IO () but () doesn't seem to BH be allowed in FFI... void f(void); foreign import ccall f :: IO () BH A third point is, how would I pass an arbitrary monad instead of just using BH IO? if you are sure what you do, you can even declare C function as pure: foreign import ccall duma_init :: Int - Int -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
On Tue, Mar 07, 2006 at 04:35:27PM -, Brian Hulley wrote: A third point is, how would I pass an arbitrary monad instead of just using IO? What for? IO is the monad that most closely matches the imperative, C semantics. That's why FFI only supports the IO monad (and pure functions). Other monads (you say arbitrary) may use rather complicated machinery to implement their semantics (HOFs, laziness, algebraic data types). I don't think it's a good idea to try implementing their actions in C (if that's what you want). Why do you need that? Best regards Tomasz -- I am searching for programmers who are good at least in (Haskell || ML) (Linux || FreeBSD || math) for work in Warsaw, Poland ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
On Tue, Mar 07, 2006 at 07:57:50PM +0100, Tomasz Zielonka wrote: On Tue, Mar 07, 2006 at 04:35:27PM -, Brian Hulley wrote: A third point is, how would I pass an arbitrary monad instead of just using IO? What for? IO is the monad that most closely matches the imperative, C semantics. That's why FFI only supports the IO monad (and pure functions). Other monads (you say arbitrary) may use rather complicated machinery to implement their semantics (HOFs, laziness, algebraic data types). I don't think it's a good idea to try implementing their actions in C (if that's what you want). Why do you need that? I tend to wrap FFI imports with functions that can be called in any MonadIO monad. I sometimes think I should suggest the FFI should be able to do this itself, but given I'm generally needing to convert types, allocate memory etc in these functions too the gain would be fairly minimal. Thanks Ian ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: How to find out the C type signature corresponding to a Haskell function type in FFI?
Bulat Ziganshin wrote: Hello Brian, Tuesday, March 7, 2006, 7:35:27 PM, you wrote: foreign import ccall duma_init :: Int - IO Int int duma_init(int); Also, I really wanted to be able to use () - IO () but () doesn't seem to be allowed in FFI... void f(void); foreign import ccall f :: IO () Thanks Bulat for these function prototypes (+ the links you posted). I'd thought that it would be complicated to deal with the IO monad but I see from these prototypes that it's not so complicated after all... :-) Best regards, Brian. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
