forked from mirrors/nixpkgs
124 lines
3.6 KiB
Nix
124 lines
3.6 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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rec {
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hasType = x: isAttrs x && x ? _type;
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typeOf = x: if hasType x then x._type else "";
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# name (name of the type)
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# check (boolean function)
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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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# path (path contatenated to the option name contained contained in the option set)
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isOptionType = attrs: typeOf attrs == "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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}:
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{ _type = "option-type";
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inherit name check merge iter fold docPath hasOptions;
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};
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types = {
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inferred = mkOptionType {
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name = "inferred type";
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};
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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 (x: builtins ? isString -> builtins.isString x);
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merge = lib.concatStrings;
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};
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attrs = mkOptionType {
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name = "attribute set";
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check = lib.traceValIfNot builtins.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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list = 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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};
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attrsOf = elemType: mkOptionType {
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name = "attribute set of ${elemType}s";
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check = x: lib.traceValIfNot builtins.isAttrs x
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&& fold (e: v: v && elemType.check e) true (lib.attrValues x);
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merge = fold lib.mergeAttrs {};
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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;
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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 tail list == [] then
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head list
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else
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throw "Multiple definitions. Only one is 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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# !!! this should be a type constructor that takes the options as
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# an argument.
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optionSet = mkOptionType {
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name = "option set";
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check = x: lib.traceValIfNot builtins.isAttrs x;
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hasOptions = true;
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};
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};
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}
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