226 lines
7.3 KiB
Nix
226 lines
7.3 KiB
Nix
# Definitions related to run-time type checking. Used in particular
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# to type-check NixOS configurations.
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let lib = import ./default.nix; in
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with import ./lists.nix;
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with import ./attrsets.nix;
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with import ./options.nix;
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with import ./trivial.nix;
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rec {
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isType = type: x: (x._type or "") == type;
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hasType = x: isAttrs x && x ? _type;
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typeOf = x: x._type or "";
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setType = typeName: value: value // {
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_type = typeName;
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};
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# name (name of the type)
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# check (check the config value. Before returning false it should trace the bad value eg using traceValIfNot)
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# merge (default merge function)
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# iter (iterate on all elements contained in this type)
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# fold (fold all elements contained in this type)
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# hasOptions (boolean: whatever this option contains an option set)
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# delayOnGlobalEval (boolean: should properties go through the evaluation of this option)
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# docPath (path concatenated to the option name contained in the option set)
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isOptionType = isType "option-type";
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mkOptionType =
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{ name
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, check ? (x: true)
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, merge ? mergeDefaultOption
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# Handle complex structure types.
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, iter ? (f: path: v: f path v)
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, fold ? (op: nul: v: op v nul)
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, docPath ? lib.id
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# If the type can contains option sets.
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, hasOptions ? false
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, delayOnGlobalEval ? false
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}:
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{ _type = "option-type";
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inherit name check merge iter fold docPath hasOptions delayOnGlobalEval;
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};
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types = rec {
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bool = mkOptionType {
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name = "boolean";
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check = lib.traceValIfNot builtins.isBool;
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merge = fold lib.or false;
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};
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int = mkOptionType {
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name = "integer";
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check = lib.traceValIfNot builtins.isInt;
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};
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string = mkOptionType {
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name = "string";
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check = lib.traceValIfNot builtins.isString;
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merge = lib.concatStrings;
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};
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# Like ‘string’, but add newlines between every value. Useful for
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# configuration file contents.
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lines = mkOptionType {
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name = "string";
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check = lib.traceValIfNot builtins.isString;
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merge = lib.concatStringsSep "\n";
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};
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envVar = mkOptionType {
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name = "environment variable";
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inherit (string) check;
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merge = lib.concatStringsSep ":";
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};
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attrs = mkOptionType {
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name = "attribute set";
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check = lib.traceValIfNot isAttrs;
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merge = fold lib.mergeAttrs {};
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};
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# derivation is a reserved keyword.
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package = mkOptionType {
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name = "derivation";
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check = lib.traceValIfNot isDerivation;
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};
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path = mkOptionType {
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name = "path";
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# Hacky: there is no ‘isPath’ primop.
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check = lib.traceValIfNot (x: builtins.unsafeDiscardStringContext (builtins.substring 0 1 (toString x)) == "/");
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};
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# drop this in the future:
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list = builtins.trace "types.list is deprecated, use types.listOf instead" types.listOf;
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listOf = elemType: mkOptionType {
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name = "list of ${elemType.name}s";
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check = value: lib.traceValIfNot isList value && all elemType.check value;
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merge = concatLists;
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iter = f: path: list: map (elemType.iter f (path + ".*")) list;
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fold = op: nul: list: lib.fold (e: l: elemType.fold op l e) nul list;
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docPath = path: elemType.docPath (path + ".*");
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inherit (elemType) hasOptions;
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# You cannot define multiple configurations of one entity, therefore
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# no reason justify to delay properties inside list elements.
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delayOnGlobalEval = false;
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};
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attrsOf = elemType: mkOptionType {
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name = "attribute set of ${elemType.name}s";
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check = x: lib.traceValIfNot isAttrs x
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&& all elemType.check (lib.attrValues x);
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merge = lib.zipAttrsWith (name: elemType.merge);
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iter = f: path: set: lib.mapAttrs (name: elemType.iter f (path + "." + name)) set;
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fold = op: nul: set: fold (e: l: elemType.fold op l e) nul (lib.attrValues set);
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docPath = path: elemType.docPath (path + ".<name>");
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inherit (elemType) hasOptions delayOnGlobalEval;
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};
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# List or attribute set of ...
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loaOf = elemType:
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let
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convertIfList = defIdx: def:
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if isList def then
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listToAttrs (
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flip imap def (elemIdx: elem:
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nameValuePair "unnamed-${toString defIdx}.${toString elemIdx}" elem))
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else
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def;
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listOnly = listOf elemType;
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attrOnly = attrsOf elemType;
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in mkOptionType {
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name = "list or attribute set of ${elemType.name}s";
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check = x:
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if isList x then listOnly.check x
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else if isAttrs x then attrOnly.check x
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else lib.traceValIfNot (x: false) x;
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## The merge function returns an attribute set
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merge = defs:
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attrOnly.merge (imap convertIfList defs);
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iter = f: path: def:
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if isList def then listOnly.iter f path def
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else if isAttrs def then attrOnly.iter f path def
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else throw "Unexpected value";
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fold = op: nul: def:
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if isList def then listOnly.fold op nul def
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else if isAttrs def then attrOnly.fold op nul def
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else throw "Unexpected value";
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docPath = path: elemType.docPath (path + ".<name?>");
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inherit (elemType) hasOptions delayOnGlobalEval;
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}
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;
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uniq = elemType: mkOptionType {
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inherit (elemType) name check iter fold docPath hasOptions;
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merge = list:
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if length list == 1 then
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head list
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else
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throw "Multiple definitions of ${elemType.name}. Only one is allowed for this option.";
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};
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none = elemType: mkOptionType {
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inherit (elemType) name check iter fold docPath hasOptions;
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merge = list:
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throw "No definitions are allowed for this option.";
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};
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nullOr = elemType: mkOptionType {
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inherit (elemType) name merge docPath hasOptions;
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check = x: builtins.isNull x || elemType.check x;
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iter = f: path: v: if v == null then v else elemType.iter f path v;
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fold = op: nul: v: if v == null then nul else elemType.fold op nul v;
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};
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functionTo = elemType: mkOptionType {
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name = "function that evaluates to a(n) ${elemType.name}";
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check = lib.traceValIfNot builtins.isFunction;
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merge = fns:
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args: elemType.merge (map (fn: fn args) fns);
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# These are guesses, I don't fully understand iter, fold, delayOnGlobalEval
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iter = f: path: v:
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args: elemType.iter f path (v args);
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fold = op: nul: v:
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args: elemType.fold op nul (v args);
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inherit (elemType) delayOnGlobalEval;
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hasOptions = false;
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};
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# usually used with listOf, attrsOf, loaOf like this:
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# users = mkOption {
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# type = loaOf optionSet;
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#
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# # you can omit the list if there is one element only
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# options = [ {
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# name = mkOption {
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# description = "name of the user"
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# ...
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# };
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# # more options here
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# } { more options } ];
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# }
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# TODO: !!! document passing options as an argument to optionSet,
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# deprecate the current approach.
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optionSet = mkOptionType {
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name = "option set";
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# merge is done in "options.nix > addOptionMakeUp > handleOptionSets"
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merge = lib.id;
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check = x: isAttrs x || builtins.isFunction x;
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hasOptions = true;
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delayOnGlobalEval = true;
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};
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};
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}
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