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Overlays: Difference between revisions
Add two examples of how to manually apply overlays in a flake context
imported>Toraritte (Move "Overlays" section from Alternative Package Sets article to here under "List of 3rd party overlays") |
imported>Niols (Add two examples of how to manually apply overlays in a flake context) |
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==== In standalone nix code ==== | ==== In standalone nix code ==== | ||
===== In a shell.nix ===== | |||
When writing standalone nix code, for example a <code>shell.nix</code> for a project, one usually starts by importing nixpkgs: <code>let pkgs = import <nixpkgs> {}</code>. To use an overlay in this context, replace that by: | When writing standalone nix code, for example a <code>shell.nix</code> for a project, one usually starts by importing nixpkgs: <code>let pkgs = import <nixpkgs> {}</code>. To use an overlay in this context, replace that by: | ||
<syntaxhighlight lang="nix"> | <syntaxhighlight lang="nix"> | ||
import <nixpkgs> { overlays = [ overlay1 overlay2 ]; } | import <nixpkgs> { overlays = [ overlay1 overlay2 ]; } | ||
</syntaxhighlight> | |||
===== In a Nix flake ===== | |||
In a Nix flake, nixpkgs will be coming from the inputs. It is common to write something like | |||
<syntaxhighlight lang="nix"> | |||
let pkgs = nixpkgs.legacyPackages.${system} | |||
</syntaxhighlight> | |||
where <code>system</code> is a variable containing eg. <code>"x86_64-linux"</code>. In order to apply overlays to this, one can do either of: | |||
<syntaxhighlight lang="nix"> | |||
let pkgs = (nixpkgs.legacyPackages.${system}.extend overlay1).extend overlay2 | |||
</syntaxhighlight> | |||
or, using the <code>import</code> function: | |||
<syntaxhighlight lang="nix"> | |||
let pkgs = import nixpkgs { inherit system; overlays = [ overlay1 overlay2 ]; } | |||
</syntaxhighlight> | </syntaxhighlight> | ||