You must declare your exported-
and other-
modules in order for Cabal to package them all together. For instance (from https://github.com/tel/happstack-heroku-test)
name: hktest -- note the name here names
-- the *library* which is a package name
-- in scope when building the executable
...
library
exposed-modules:
HKTest
other-modules:
-- there aren't any, but there could be some
build-depends: base >= 4.6 && <4.7
...
, mtl >= 2.1.2
hs-source-dirs: src
executable server
main-is: Server.hs
other-modules:
-- there might be some use to having these here,
-- but they'll be harder to get into GHCi, so I wouldn't
-- recommend it---just put them in the library part
build-depends: base >=4.6 && <4.7
, hktest -- note that I grab all the hktest
-- modules here
hs-source-dirs: exe
If I leave out one of those modules I'll likely get a build error as Cabal compiles files which expect to be able to find symbols that haven't been packaged.
In your case, since you're building an executable, the common pattern exemplified above is to put all of your code into a library and then have the executable side depend upon that library. For instance, in this example the complete text of exe/Server.hs
is
module Main where
import qualified HKTest as HK
main :: IO ()
main = HK.main