diff options
Diffstat (limited to 'src/libexpr')
| -rw-r--r-- | src/libexpr/eval-settings.hh | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/libexpr/eval-settings.hh b/src/libexpr/eval-settings.hh index c264b521f..98fe6881e 100644 --- a/src/libexpr/eval-settings.hh +++ b/src/libexpr/eval-settings.hh @@ -125,6 +125,42 @@ struct EvalSettings : Config This is useful for debugging warnings in third-party Nix code. )"}; + + PathsSetting replOverlays{this, Paths(), "repl-overlays", + R"( + A list of files containing Nix expressions that can be used to add + default bindings to [`nix + repl`](@docroot@/command-ref/new-cli/nix3-repl.md) sessions. + + Each file is called with three arguments: + 1. An [attribute set](@docroot@/language/values.html#attribute-set) + containing at least a + [`currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem) + attribute (this is identical to + [`builtins.currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem), + except that it's available in + [`pure-eval`](@docroot@/command-ref/conf-file.html#conf-pure-eval) + mode). + 2. The top-level bindings produced by the previous `repl-overlays` + value (or the default top-level bindings). + 3. The final top-level bindings produced by calling all + `repl-overlays`. + + For example, the following file would alias `pkgs` to + `legacyPackages.${info.currentSystem}` (if that attribute is defined): + + ```nix + info: final: prev: + if prev ? legacyPackages + && prev.legacyPackages ? ${info.currentSystem} + then + { + pkgs = prev.legacyPackages.${info.currentSystem}; + } + else + { } + ``` + )"}; }; extern EvalSettings evalSettings; |