Rebecca Turner
727b43478c
Adds a `repl-overlays` option, which specifies files that can overlay
and modify the top-level bindings in `nix repl`. For example, with the
following contents in `~/.config/nix/repl.nix`:
info: final: prev: let
optionalAttrs = predicate: attrs:
if predicate
then attrs
else {};
in
optionalAttrs (prev ? legacyPackages && prev.legacyPackages ? ${info.currentSystem})
{
pkgs = prev.legacyPackages.${info.currentSystem};
}
We can run `nix repl` and use `pkgs` to refer to `legacyPackages.${currentSystem}`:
$ nix repl --repl-overlays ~/.config/nix/repl.nix nixpkgs
Lix 2.90.0
Type :? for help.
Loading installable 'flake:nixpkgs#'...
Added 5 variables.
Loading 'repl-overlays'...
Added 6 variables.
nix-repl> pkgs.bash
«derivation /nix/store/g08b5vkwwh0j8ic9rkmd8mpj878rk62z-bash-5.2p26.drv»
Change-Id: Ic12e0f2f210b2f46e920c33088dfe1083f42391a
8 lines
183 B
Nix
8 lines
183 B
Nix
info: final: prev:
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{
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var = prev.var + "b";
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# We can access the final value of `var` here even though it isn't defined yet:
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varUsingFinal = "final value is: " + final.newVar;
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}
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