Compile the module from bottom to top, with -c. Then link. THus ghc -c MyList.hs ghc -c ListFun.hs ...etc... ghc -c Main.hs ghc -o MyApp MyList.o ListFun.o ... Main.o Simon | -----Original Message----- | From: Ingo Sander [mailto:ingo@ele.kth.se] | Sent: 20 October 2000 17:09 | To: glasgow-haskell-users@haskell.org | Subject: Interface Files _ HOWTO? | | | After working a lot with Hugs I tried to compile my Haskell | code with GHC. | But it does not work, I am not able to figure out how to work with the | interface files (.hi). My program is build out of several | modules, like | this (much simpler, but facing the same problem...) | | File MyList.hs | ============== | | module MyList(MkList(Empty, (:-))) where | | infixr 5 :- | | data MkList a = Empty | | a :- (MkList a) deriving (Eq, Show) | | | File ListFun.hs | =============== | | module ListFun(mapL) where | | import MyList | | mapL f Empty = Empty | mapL f (x:-xs) = f x :- mapL f xs | | | | File ListLib | ============ | | module ListLib(module MyList, module ListFun) where | | import MyList | import ListFun | | | File Main.hs | ============ | | module Main(main) where | | import ListLib | | main = putStr (show (mapL (+1) (1:-2:-Empty))) | | | | As I said the code works with hugs, and I want to have the | hierarchy in | the library structure. | | So, how do I compile this in GHC? I hoped, that it would be enough to | compile all files with the -c option (generating .hi and .o files) and | then compiling Main.hs to get an executable program. Howeve, I get the | following: | | > ghc Main.hs | ghc: module version unchanged at 7 | Undefined first referenced | symbol in file | MyList_ZCzm_con_info Main.o | MyList_zdfShowMkList_closure Main.o | ListFun_mapL_closure Main.o | MyList_Empty_static_closure Main.o | ld: fatal: Symbol referencing errors. No output written to a.out | | So, what's wrong, and am I totally on the wrong track... (I | studied the | GHC User Guide, but could not find the answer to my problem). | | Thanks in advance! | | Ingo Sander | | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users |