harry
I've written a library, and a simple program to demonstrate it. I can write the cabal file for the library, but I can't get the executable section right. How can I tell it to use the library defined herein?
You need two things for this to work properly. Firstly you need to require a sufficiently recent Cabal version, for example: name: mylib version: 0.1.0 cabal-version: >= 1.10 library -- ... Secondly to avoid double-compilation you should put your program's source code in a different tree. My personal approach is to put the library's source code right within the project's root directory, but the executable's source code below a subdirectory called 'program', so the Main module is in 'program/Main.hs'. Then just mention the package itself as a dependency: executable myprog build-depends: base >= 4.5 && < 5, mylib default-language: Haskell2010 ghc-options: -W -threaded -rtsopts hs-source-dirs: program main-is: Main.hs If the program is just a demo that you wouldn't normally want to install with the library, you can make it a test suite instead of an executable: test-suite mylib-demo type: exitcode-stdio-1.0 build-depends: base >= 4.5 && < 5, mylib default-language: Haskell2010 ghc-options: -W -threaded -rtsopts hs-source-dirs: program main-is: Main.hs That way the executable is only built when you configure with --enable-tests and isn't installed together with the library. However, keep in mind that if you have an actual test suite the demo program will be run along with it when you command 'cabal test': test-suite mylib-props -- ... To avoid that just invoke your test suite on the command line instead of through 'cabal test': ln -s dist/build/tests/tests ./tests Greets, Ertugrul -- Not to be or to be and (not to be or to be and (not to be or to be and (not to be or to be and ... that is the list monad.