{
  inputs,
  tree,
  systems,
}: let
  nixlib = inputs.nixpkgs.lib;
  inherit (nixlib.modules) mkOrder mkOverride defaultOverridePriority;
  inherit (nixlib.strings) splitString toLower;
  inherit (nixlib.lists) imap0 elemAt findFirst foldl;
  inherit (nixlib.attrsets) mapAttrs listToAttrs nameValuePair;
  inherit (nixlib.strings) hasPrefix hasInfix removePrefix substring fixedWidthString replaceStrings concatMapStringsSep stringToCharacters match toInt;
  inherit (nixlib.trivial) flip toHexString bitOr;

  toHexStringLower = v: toLower (toHexString v);

  hexCharToInt = let
    hexChars = ["0" "1" "2" "3" "4" "5" "6" "7" "8" "9" "a" "b" "c" "d" "e" "f"];
    pairs = imap0 (flip nameValuePair) hexChars;
    idx = listToAttrs pairs;
  in
    char: idx.${char};
  hexToInt = str: foldl (value: chr: value * 16 + hexCharToInt chr) 0 (stringToCharacters (toLower str));

  eui64 = mac: let
    parts = map toLower (splitString ":" mac);
    part = elemAt parts;
    part0 = part: let
      nibble1' = hexCharToInt (substring 1 1 part);
      nibble1 = bitOr 2 nibble1';
      nibble0 = substring 0 1 part;
    in
      nibble0 + (fixedWidthString 1 "0" (toHexStringLower nibble1));
  in "${part0 (part 0)}${part 1}:${part 2}ff:fe${part 3}:${part 4}${part 5}";

  parseUrl = url: let
    parts = match ''^([^:]+)://(\[[0-9a-fA-F:]+]|[^/:\[]+)(|:[0-9]+)(|/.*)$'' url;
    port' = elemAt parts 2;
  in assert parts != null; rec {
    inherit url parts;
    scheme = elemAt parts 0;
    host = elemAt parts 1;
    port = if port' != "" then toInt (removePrefix ":" port') else null;
    hostport = host + port';
    path = elemAt parts 3;
  };

  userIs = group: user: builtins.elem group (user.extraGroups ++ [user.group]);

  mkWinPath = replaceStrings ["/"] ["\\"];
  mkBaseDn = domain: concatMapStringsSep "," (part: "dc=${part}") (splitString "." domain);
  mkAddress6 = addr: if hasInfix ":" addr && ! hasPrefix "[" addr then "[${addr}]" else addr;

  coalesce = findFirst (v: v != null) null;
  mapListToAttrs = f: l: listToAttrs (map f l);

  overrideOptionDefault = 1500;
  overrideAlmostOptionDefault = 1400;
  overrideDefault = 1000;
  overrideAlmostDefault = 900;
  overrideNone = defaultOverridePriority; # 100
  overrideAlmostForce = 75;
  overrideForce = 50;
  overrideVM = 10;
  mkAlmostOptionDefault = mkOverride overrideAlmostOptionDefault;
  mkAlmostDefault = mkOverride overrideAlmostDefault;
  mkAlmostForce = mkOverride overrideAlmostForce;
  orderJustBefore = 400;
  orderBefore = 500;
  orderAlmostBefore = 600;
  orderNone = 1000;
  orderAlmostAfter = 1400;
  orderAfter = 1500;
  orderJustAfter = 1600;
  mkJustBefore = mkOrder orderJustBefore;
  mkAlmostBefore = mkOrder orderAlmostBefore;
  mkAlmostAfter = mkOrder orderAlmostAfter;
  mkJustAfter = mkOrder orderJustAfter;
  mapOverride = priority: mapAttrs (_: mkOverride priority);
  mapOptionDefaults = mapOverride overrideOptionDefault;
  mapAlmostOptionDefaults = mapOverride overrideAlmostOptionDefault;
  mapDefaults = mapOverride overrideDefault;

  treeToModulesOutput = modules:
    {
      ${
        if modules ? __functor
        then "default"
        else null
      } =
        modules.__functor modules;
    }
    // builtins.removeAttrs modules ["__functor"];
in {
  inherit tree nixlib inputs systems;
  meta = tree.impure;
  std = inputs.self.lib.Std.Std.compat;
  Std = inputs.std-fl.lib;
  lib = {
    domain = "gensokyo.zone";
    inherit treeToModulesOutput userIs
      eui64 parseUrl mkWinPath mkBaseDn mkAddress6
      toHexStringLower hexToInt hexCharToInt
      mapListToAttrs coalesce
      mkAlmostOptionDefault mkAlmostDefault mkAlmostForce mapOverride mapOptionDefaults mapAlmostOptionDefaults mapDefaults
      overrideOptionDefault overrideAlmostOptionDefault overrideDefault overrideAlmostDefault overrideNone overrideAlmostForce overrideForce overrideVM
      orderJustBefore orderBefore orderAlmostBefore orderNone orderAfter orderAlmostAfter orderJustAfter
      mkJustBefore mkAlmostBefore mkAlmostAfter mkJustAfter;
    inherit (inputs.arcexprs.lib) unmerged json;
  };
  gensokyo-zone = {
    inherit inputs;
    inherit (inputs) self;
    inherit (inputs.self) overlays;
    inherit (inputs.self.lib) tree meta lib systems;
  };
  generate = import ./generate.nix {inherit inputs tree;};
}