jade
272db8af1b
This does not add missing release notes, and it doesn't do anything
about the profiles feature we would really like to have so we can have
consistent credit.
Change-Id: I72a6f7acfcff85f380be17dac76501a6f4693776
40 lines
990 B
Markdown
40 lines
990 B
Markdown
---
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synopsis: Add `repl-overlays` option
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prs: 10203
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cls: 504
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credits: 9999years
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significance: significant
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category: Features
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---
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A `repl-overlays` option has been added, which specifies files that can overlay
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and modify the top-level bindings in `nix repl`. For example, with the
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following contents in `~/.config/nix/repl.nix`:
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```nix
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info: final: prev: let
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optionalAttrs = predicate: attrs:
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if predicate
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then attrs
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else {};
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in
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optionalAttrs (prev ? legacyPackages && prev.legacyPackages ? ${info.currentSystem})
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{
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pkgs = prev.legacyPackages.${info.currentSystem};
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}
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```
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We can run `nix repl` and use `pkgs` to refer to `legacyPackages.${currentSystem}`:
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```ShellSession
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$ nix repl --repl-overlays ~/.config/nix/repl.nix nixpkgs
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Lix 2.90.0
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Type :? for help.
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Loading installable 'flake:nixpkgs#'...
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Added 5 variables.
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Loading 'repl-overlays'...
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Added 6 variables.
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nix-repl> pkgs.bash
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«derivation /nix/store/g08b5vkwwh0j8ic9rkmd8mpj878rk62z-bash-5.2p26.drv»
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```
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