rtx: add module (#4051)

modules/programs/rtx.nix

@@ -0,0 +1,81 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.rtx;
+  tomlFormat = pkgs.formats.toml { };
+in {
+  meta.maintainers = [ hm.maintainers.pedorich-n ];
+
+  options = {
+    programs.rtx = {
+      enable = mkEnableOption "RTX. Runtime Executor (asdf Rust clone)";
+
+      package = mkPackageOption pkgs "rtx" { };
+
+      enableBashIntegration = mkEnableOption "Bash Integration" // {
+        default = true;
+      };
+
+      enableZshIntegration = mkEnableOption "Zsh Integration" // {
+        default = true;
+      };
+
+      enableFishIntegration = mkEnableOption "Fish Integration" // {
+        default = true;
+      };
+
+      settings = mkOption {
+        type = tomlFormat.type;
+        default = { };
+        example = literalExpression ''
+          tools = {
+            node = "lts";
+            python = ["3.10" "3.11"];
+          };
+
+          settings = {
+            verbose = false;
+            experimental = false;
+          };
+        '';
+        description = ''
+          Settings written to <filename>$XDG_CONFIG_HOME/rtx/config.toml</filename>.
+          </para><para>
+          See <link xlink:href="https://github.com/jdxcode/rtx#global-config-configrtxconfigtoml"/>
+          for details on supported values.
+
+          <warning>
+            <para>
+              Modifying the <literal>tools</literal> section doesn't make RTX install them. 
+              You have to manually run <literal>rtx install</literal> to install the tools.
+            </para>
+          </warning>
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ cfg.package ];
+
+    xdg.configFile."rtx/config.toml" = mkIf (cfg.settings != { }) {
+      source = tomlFormat.generate "rtx-settings" cfg.settings;
+    };
+
+    programs = {
+      bash.initExtra = mkIf cfg.enableBashIntegration ''
+        eval "$(${getExe cfg.package} activate bash)"
+      '';
+
+      zsh.initExtra = mkIf cfg.enableZshIntegration ''
+        eval "$(${getExe cfg.package} activate zsh)"
+      '';
+
+      fish.interactiveShellInit = mkIf cfg.enableFishIntegration ''
+        ${getExe cfg.package} activate fish | source
+      '';
+    };
+  };
+}