Created
August 7, 2018 00:24
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Build a multi-project Cabal application with Nix
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with builtins; rec { | |
cabalProjects = listToAttrs (if pathExists ./cabal.project | |
then projectParse | |
else [ { name = baseNameOf ./.; value = ./.; } ] ); | |
projectParse = let | |
contents = readFile ./cabal.project; | |
trimmed = replaceStrings ["packages:" " "] ["" ""] contents; | |
packages = filter (x: isString x && x != "") (split "\n" trimmed); | |
package = p: substring 0 (stringLength p - 1) p; | |
paths = map (p: let p' = package p; in { name = p'; value = toPath (./. + "/${p'}"); } ) packages; | |
in paths; | |
}.cabalProjects |
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{forShell ? false}: | |
let | |
pkgs = import ./nixpkgs.nix {}; | |
ghc = pkgs.haskell.packages.ghc822; | |
targets = import ./cabal.nix; | |
haskellPackages = ghc.extend (pkgs.lib.composeExtensions | |
(pkgs.haskell.lib.packageSourceOverrides (targets // { | |
# any version overrides or submodule package dependencies here | |
# some-package = "0.2.0.0"; # fetch specific hackage version | |
# some-package = ./dir/subproject; # git submodule packages | |
})) | |
(self: super: { | |
ghcWithPackages = p: super.ghcWithPackages ( | |
# I like to have ghci-pretty and ghcid available in my nix-shell | |
f: p f ++ (if forShell then [ f.cabal-install f.ghci-pretty f.ghcid ] else []) | |
); | |
# any fetch/overrides go here | |
# some-package = pkgs.haskell.lib.dontCheck (self.callCabal2nix "some-package" (pkgs.fetchFromGitHub { ... }) {}); | |
# some-package = pkgs.haskell.lib.overrideCabal super.some-package (drv: { patches = (drv.patches or [ ... ]); }); | |
}) | |
); | |
buildSet = pkgs.lib.foldl (ps: p: ps // { ${p.pname} = p; }) {} packages; | |
packages = map (t: haskellPackages.${t} ) (builtins.attrNames targets); | |
tools = [ pkgs.pkgconfig ]; | |
in | |
if forShell | |
then haskellPackages.shellFor { packages = _: packages; buildInputs = tools; } | |
else buildSet |
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import ./. { forShell = true; } |
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This could be much simpler:
cabal.project:
default.nix:
Full setup => https://github.com/ip1981/hakyll-template/tree/master/compiler