Udo Stenzel:
Duncan Coutts wrote:
Manuel may well have some comments on the issues you've brought up but he's often quite busy so you may like to start discussing/hacking the least controversial bits.
And so I did. Attached is a path that defers the error about variadic functions a bit. This was surprisingly simple, it basically worked on the first try. Now I can write get hooks for the "methods" in libdb, and if I manually write lots of foreign import dynamic declarations, I call call them.
Good work! I just added the patch to the public repo.
The next step is to generate them. I think, the easiest way is to extend the call and fun hooks to accept cids of the form struct->method, which would then create a dynamic import and act like a combination of get and call hooks. Libdb always passes the struct itself as the first argument to the method. This seems to be a fairly common convention. Do you think it deserves special support?
I actually looked at Sleepy Cat's LibDB myself at some point, but then never got around to doing anything about it. I remember their OOish set up. Your plan sounds reasonable. As for the struct as the first argument, I think it is a common pattern, but I it might be a bit awkward to implement. If it is, maybe leave it for a second round. Fun hooks share the `callImport' function with call hooks, which is what generates the import declaration (this is in c2hs/gen/GenBind.hs). The struct-method variant should also be able to share code like this (but I guess, you figured that out already anyway). In a previous message, you asked,
- defines. Am I right in assuming that c2hs does not recognize #define'd constant and so cannot reflect them in Haskell?
Correct. There is a plan to add some support for this to enum hooks, but I never got around to implement that. I currently suggest to use inline C in .chs file to bind #define'd enums. See c2hs/tests/Enum.chs for an example (the ThisThat definition). Thanks for the code! Manuel