move nixlang impls to their own directory tree

modules/dynamicism/default.nix

@@ -0,0 +1,73 @@
+{ pkgs, lib, config, options, ... }:
+let
+  inherit (lib.modules)
+    mkIf
+  ;
+  inherit (lib.options)
+    mkOption
+    mkEnableOption
+    literalExpression
+    showOption
+  ;
+  t = lib.types;
+  cfg = config.dynamicism;
+
+  settingsFormat = pkgs.formats.yaml { };
+
+  assertionFor = submodName: unitName: let
+    optName = [ "dynamicism" "for" submodName "systemd-services-updated" ];
+  in {
+    assertion = config.systemd.units.${unitName}.enable or false;
+    message = "'${showOption optName}' specified non-existentant unit '${unitName}'";
+  };
+
+  assertionsFor =
+    submodName:
+    submod:
+    lib.map (assertionFor submodName) submod.systemd-services-updated;
+
+  finalSettingsFor = { ... }@submod: lib.foldl (acc: optPath: let
+    next =
+      assert lib.isList optPath;
+      lib.setAttrByPath optPath (lib.getAttrFromPath optPath config);
+  in lib.recursiveUpdate acc next) { } submod.source-options;
+in
+{
+  options.dynamicism = {
+    for = mkOption {
+      type = t.attrsOf (t.submoduleWith {
+        modules = [ ./submodule.nix ];
+        shorthandOnlyDefinesConfig = false;
+      });
+      default = { };
+    };
+
+    finalSettings = mkOption {
+      type = t.attrsOf t.raw;
+      internal = true;
+      readOnly = true;
+      description = ''
+        Attrset of each `source-options` tree to their actual values.
+      '';
+    };
+  };
+
+  config.assertions = lib.foldlAttrs (acc: name: submod: let
+    next = lib.optionals submod.enable (assertionsFor name submod);
+  in acc ++ next) [ ] cfg.for;
+
+  config.dynamicism.for = {
+    gotosocial = {
+      source-options = [
+        "services.gotosocial.settings"
+      ];
+      systemd-services-updated = [
+        "gotosocial.service"
+      ];
+    };
+  };
+
+  config.dynamicism.finalSettings = lib.foldlAttrs (acc: name: { ... }@submod: let
+    next = finalSettingsFor submod;
+  in lib.recursiveUpdate acc next) { } config.dynamicism.for;
+}