mirror of
https://github.com/simplex-chat/haskell.nix.git
synced 2026-06-03 09:17:32 +00:00
Toon NoltenandMoritz Angermann
7874deb621
* Updated the haskell.nix imports to overlay style Some of the examples in the documentation were still passing an empty set to the haskell.nix imports but this is no longer valid because the import now results in a set rather than a function. * Fix overlay imports in docs Import an overlayed nixpkgs rather than just the overlay. Thanks to angerman for noticing this error.
59 lines
1.5 KiB
Markdown
59 lines
1.5 KiB
Markdown
Here we will look into how to generate the `pkgs.nix` file for a
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`stack.yaml` project. For the full integration see the
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[previous page](./projects.md).
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## Using `stack-to-nix`
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With [nix-tools installed](../user-guide.md), we can simply run the
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following command on a stack project:
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```bash
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stack-to-nix --output . --stack-yaml stack.yaml
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```
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This will produce a `pkgs.nix` file that looks like the following:
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```nix
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{
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resolver = "lts-12.17";
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extras = hackage:
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{
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packages = {
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"o-clock" = hackage.o-clock."0.1.1".revisions.default;
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...
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} // {
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my-package = ./my-package.nix;
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...
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};
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};
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}
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```
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This file contains the stackage resolver, as well as set of extra
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packages. The extras specifies which `extra-deps` (here:
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`o-clock-0.1.1`) we wanted to add over the stackage snapshot, and what
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local packages we want (here: `my-package`).
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## Creating the package set
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Import the generated `pkgs.nix` and pass to
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[`mkStackPkgSet`](../reference/library.md#mkstackpkgset) to
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instantiate a package set.
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```nix
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# default.nix
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let
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# Import the Haskell.nix library,
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src = builtins.fetchTarball https://github.com/input-output-hk/haskell.nix/archive/master.tar.gz;
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nixpkgs = import (src + "/nixpkgs") (import src);
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haskell = nixpkgs.haskell-nix;
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# Instantiate a package set using the generated file.
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pkgSet = haskell.mkStackPkgSet {
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stack-pkgs = import ./pkgs.nix;
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pkg-def-overlays = [];
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modules = [];
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};
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in
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pkgSet.config.hsPkgs
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```
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