/* Library of low-level helper functions for nix expressions.
 *
 * Please implement (mostly) exhaustive unit tests
 * for new functions in `./tests.nix'.
 */
let

  callLibs = file: import file { inherit lib; };

  lib = rec {

    # often used, or depending on very little
    trivial = callLibs ./trivial.nix;
    fixedPoints = callLibs ./fixed-points.nix;

    # datatypes
    attrsets = callLibs ./attrsets.nix;
    lists = callLibs ./lists.nix;
    strings = callLibs ./strings.nix;
    stringsWithDeps = callLibs ./strings-with-deps.nix;

    # packaging
    customisation = callLibs ./customisation.nix;
    maintainers = callLibs ./maintainers.nix;
    meta = callLibs ./meta.nix;
    sources = callLibs ./sources.nix;
    versions = callLibs ./versions.nix;

    # module system
    modules = callLibs ./modules.nix;
    options = callLibs ./options.nix;
    types = callLibs ./types.nix;

    # constants
    licenses = callLibs ./licenses.nix;
    systems = callLibs ./systems;

    # misc
    debug = callLibs ./debug.nix;

    generators = callLibs ./generators.nix;
    misc = callLibs ./deprecated.nix;
    # domain-specific
    fetchers = callLibs ./fetchers.nix;

    # Eval-time filesystem handling
    filesystem = callLibs ./filesystem.nix;

    # back-compat aliases
    platforms = systems.doubles;

    inherit (builtins) add addErrorContext attrNames
      concatLists deepSeq elem elemAt filter genericClosure genList
      getAttr hasAttr head isAttrs isBool isInt isList
      isString length lessThan listToAttrs pathExists readFile
      replaceStrings seq stringLength sub substring tail;
    inherit (trivial) id const concat or and boolToString mergeAttrs
      flip mapNullable inNixShell min max importJSON warn info
      nixpkgsVersion mod compare splitByAndCompare
      functionArgs setFunctionArgs isFunction;

    inherit (fixedPoints) fix fix' extends composeExtensions
      makeExtensible makeExtensibleWithCustomName;
    inherit (attrsets) attrByPath hasAttrByPath setAttrByPath
      getAttrFromPath attrVals attrValues catAttrs filterAttrs
      filterAttrsRecursive foldAttrs collect nameValuePair mapAttrs
      mapAttrs' mapAttrsToList mapAttrsRecursive mapAttrsRecursiveCond
      genAttrs isDerivation toDerivation optionalAttrs
      zipAttrsWithNames zipAttrsWith zipAttrs recursiveUpdateUntil
      recursiveUpdate matchAttrs overrideExisting getOutput getBin
      getLib getDev chooseDevOutputs zipWithNames zip;
    inherit (lists) singleton foldr fold foldl foldl' imap0 imap1
      concatMap flatten remove findSingle findFirst any all count
      optional optionals toList range partition zipListsWith zipLists
      reverseList listDfs toposort sort compareLists take drop sublist
      last init crossLists unique intersectLists subtractLists
      mutuallyExclusive;
    inherit (strings) concatStrings concatMapStrings concatImapStrings
      intersperse concatStringsSep concatMapStringsSep
      concatImapStringsSep makeSearchPath makeSearchPathOutput
      makeLibraryPath makeBinPath makePerlPath optionalString
      hasPrefix hasSuffix stringToCharacters stringAsChars escape
      escapeShellArg escapeShellArgs replaceChars lowerChars upperChars
      toLower toUpper addContextFrom splitString removePrefix
      removeSuffix versionOlder versionAtLeast getVersion nameFromURL
      enableFeature fixedWidthString fixedWidthNumber isStorePath
      toInt readPathsFromFile fileContents;
    inherit (stringsWithDeps) textClosureList textClosureMap
      noDepEntry fullDepEntry packEntry stringAfter;
    inherit (customisation) overrideDerivation makeOverridable
      callPackageWith callPackagesWith extendDerivation
      hydraJob makeScope;
    inherit (meta) addMetaAttrs dontDistribute setName updateName
      appendToName mapDerivationAttrset lowPrio lowPrioSet hiPrio
      hiPrioSet;
    inherit (sources) pathType pathIsDirectory cleanSourceFilter
      cleanSource sourceByRegex sourceFilesBySuffices
      commitIdFromGitRepo cleanSourceWith pathHasContext canCleanSource;
    inherit (modules) evalModules closeModules unifyModuleSyntax
      applyIfFunction unpackSubmodule packSubmodule mergeModules
      mergeModules' mergeOptionDecls evalOptionValue mergeDefinitions
      pushDownProperties dischargeProperties filterOverrides
      sortProperties fixupOptionType mkIf mkAssert mkMerge mkOverride
      mkOptionDefault mkDefault mkForce mkVMOverride mkStrict
      mkFixStrictness mkOrder mkBefore mkAfter mkAliasDefinitions
      mkAliasAndWrapDefinitions fixMergeModules mkRemovedOptionModule
      mkRenamedOptionModule mkMergedOptionModule mkChangedOptionModule
      mkAliasOptionModule doRename filterModules;
    inherit (options) isOption mkEnableOption mkSinkUndeclaredOptions
      mergeDefaultOption mergeOneOption mergeEqualOption getValues
      getFiles optionAttrSetToDocList optionAttrSetToDocList'
      scrubOptionValue literalExample showOption showFiles
      unknownModule mkOption;
    inherit (types) isType setType defaultTypeMerge defaultFunctor
      isOptionType mkOptionType;
    inherit (debug) addErrorContextToAttrs traceIf traceVal
      traceXMLVal traceXMLValMarked traceSeq traceSeqN traceValSeq
      traceValSeqN traceShowVal traceShowValMarked
      showVal traceCall traceCall2 traceCall3 traceValIfNot runTests
      testAllTrue strict traceCallXml attrNamesToStr;
    inherit (misc) maybeEnv defaultMergeArg defaultMerge foldArgs
      defaultOverridableDelayableArgs composedArgsAndFun
      maybeAttrNullable maybeAttr ifEnable checkFlag getValue
      checkReqs uniqList uniqListExt condConcat lazyGenericClosure
      innerModifySumArgs modifySumArgs innerClosePropagation
      closePropagation mapAttrsFlatten nvs setAttr setAttrMerge
      mergeAttrsWithFunc mergeAttrsConcatenateValues
      mergeAttrsNoOverride mergeAttrByFunc mergeAttrsByFuncDefaults
      mergeAttrsByFuncDefaultsClean mergeAttrBy
      prepareDerivationArgs nixType imap overridableDelayableArgs;
  };
in lib