cabal repl –ghc-option=’-package xyz’ This will load the package you are calling cabal repl from and the package xyz. To do that after the fact, i.e. when you’re already in the REPL and want to load an extra helper module from another package: GHCi> :set -package xyz GHCi> :m +XYZ.Module.You.Suddenly.Need
In my case (and probably others?) cabal is initially installed in /usr/local/bin by homebrew when installing haskell-platform. When upgrading cabal, the version is installed to $HOME/.cabal/bin/cabal. You ought to place your cabal bins higher in your $PATH, like so: export PATH=$HOME/.cabal/bin:$PATH
We can simply do: cabal list –installed
You need ghci -package such-and-such And to double-check that such-and-such is truly visible to GHC, run ghc-pkg list | grep such-and-such.
Graphically, the dependencies are: Packages GHC can use | Are registered with “ghc-pkg register” | And (almost always) built with Cabal | With build dependencies resolved by cabal-install | From Hackage.
The flag is -with-rtsopts, not –with-rtsopts, so you should add -with-rtsopts=-N to the ghc-options field. GHC Flag Reference. Note that this will also require you to link with runtime support by adding -rtsopts to the ghc-options.
For stack <1.11: The documentation for the stack.yaml packages section gives examples of referring to more complex package locations. packages: – location: . – location: dir1/dir2 – location: https://example.com/foo/bar/baz-0.0.2.tar.gz – location: http://github.com/yesodweb/wai/archive/2f8a8e1b771829f4a8a77c0111352ce45a14c30f.zip – location: git: git@github.com:commercialhaskell/stack.git commit: 6a86ee32e5b869a877151f74064572225e1a0398 – location: hg: https://example.com/hg/repo commit: da39a3ee5e6b4b0d3255bfef95601890afd80709 Then add extra-dep: true to the package entry just to tell … Read more
According to this ticket on the stack issue tracker, Stack can currently only build documentation for libraries, but not executables. Cabal can be configured to work with the stack databases with this command: cabal configure –package-db=clear –package-db=global –package-db=$(stack path –snapshot-pkg-db) –package-db=$(stack path –local-pkg-db) after which you can run cabal haddock –executables to generate the documentation. … Read more
Newer versions of Cabal let you specify constraints in your cabal.project.local or cabal.project file. For example: constraints: hmatrix +openblas Is there any way to indicate in my application’s .cabal file that I depend on a library so that it is built with the specific build flag? No, but in your case this is not actually … Read more
I do all my development using Nix and cabal these days, and I can happily say that they work in harmony very well. My current workflow is very new, in that it relies on features in nixpkgs that have only just reached the master branch. As such, the first thing you’ll need to do is … Read more