switch to elvish shell

home-manager/modules/elvish.nix

@@ -0,0 +1,82 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; let
+  cfg = config.programs.elvish;
+in {
+  options.programs.elvish = {
+    enable = mkEnableOption "Elvish, a friendly interactive shell and an expressive programming";
+
+    defaultFromBash = mkOption {
+      type = types.bool;
+      default = cfg.enable;
+      description = ''
+        Launch automatically when an interactive Bash shell is started
+      '';
+    };
+
+    zoxide = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Enable zoxide smart directory switcher
+      '';
+    };
+
+    starship = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Use the starship prompt
+      '';
+    };
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.elvish;
+      defaultText = literalExpression "pkgs.elvish";
+      description = ''
+        The elvish package to install. May be used to change the version.
+      '';
+    };
+
+    initExtra = mkOption {
+      type = types.lines;
+      default = "";
+      description = ''
+        Elvish code called during interactive elvish shell
+        initialisation.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [cfg.package];
+
+    # programs.man.generateCaches = mkDefault true;
+
+    xdg.configFile."elvish/rc.elv".text = cfg.initExtra;
+
+    programs.bash.enable = mkIf cfg.defaultFromBash true;
+    programs.bash.initExtra = mkIf cfg.defaultFromBash "exec elvish";
+
+    programs.starship.enable = mkIf cfg.starship true;
+    programs.zoxide.enable = mkIf cfg.zoxide true;
+
+    programs.starship.enableBashIntegration = mkIf cfg.defaultFromBash false;
+
+    programs.elvish.initExtra = mkMerge [
+      (mkIf cfg.starship ''
+        if (and (not-eq $E:TERM "dumb") (or (not (has-env "INSIDE_EMACS")) (eq $E:INSIDE_EMACS "vterm"))) {
+          eval (${config.home.profileDirectory}/bin/starship init elvish)
+        }
+      '')
+      (mkIf cfg.zoxide ''
+        eval (${config.programs.zoxide.package}/bin/zoxide init elvish | slurp)
+      '')
+    ];
+  };
+}