Cabal
The Haskell Cabal The Common Architecture for Building Applications and Libraries
Building Dlls on Windows with Cabal
Cabal does not currently support building dlls on windows out of the box. Some details about why can be found here: http://www.haskell.org/ghc/docs/6.4.2/html/users_guide/packages.html http://www.haskell.org/ghc/docs/6.4.2/html/users_guide/win32-dlls.html
This means that we have to do a bit of hackery to get Cabal to build a dll from a library. As long as we build a single DLL from the entire project the dll should behave as expected.
The following Setup.lhs should do the trick for most projects which consist of a single library which needs to be built as a dll. If you need to specify a dll export file you'll need to modify the function cmd to take this into account.
#! /usr/bin/runghc
> import Distribution.Simple
> import Distribution.Simple.LocalBuildInfo
> import Distribution.PackageDescription
> import System.Cmd
> import System.Directory
> import Data.List
>
>
> main = defaultMainWithHooks (defaultUserHooks { postBuild = buildDll })
> where
> buildDll _ _ pkg info = do putStrLn "Building Dll..."
> setCurrentDirectory (buildDir info)
> let buildCmd = cmd pkg info
> putStrLn buildCmd
> system buildCmd
> let cpCmd = "cp "++(dllFile pkg)++" "++(name pkg)++"\\"++(dllFile pkg)
> putStrLn cpCmd
> system cpCmd
> ghcExe :: LocalBuildInfo -> String
> ghcExe info = "\"" ++ (compilerPath (compiler info)) ++ "\""
> mainOFile :: PackageDescription -> String
> mainOFile pd = "HS" ++ (name pd) ++ "-" ++ (showVersion (pkgVersion (package pd))) ++ ".o"
> cmd :: PackageDescription -> LocalBuildInfo -> String
> cmd pd i = (ghcExe i) ++ " --mk-dll -o " ++ (dllFile pd) ++ " " ++ (mainOFile pd) ++ " " ++ (packages i)
> packages :: LocalBuildInfo -> String
> packages i = foldl1 (\x y -> x ++ " " ++ y) (map showPackage (packageDeps i))
> showPackage :: PackageIdentifier -> String
> showPackage pi = "-package " ++ showPackageId pi
> name :: PackageDescription -> String
> name = pkgName . package
> dllFile :: PackageDescription -> String
> dllFile pd = (name pd) ++ ".dll"