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400 lines
14 KiB
Nix
400 lines
14 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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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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with import ./strings.nix;
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let inherit (import ./modules.nix) mergeDefinitions filterOverrides; in
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rec {
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isType = type: x: (x._type or "") == type;
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setType = typeName: value: value // {
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_type = typeName;
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};
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# Default type merging function
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# takes two type functors and return the merged type
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defaultTypeMerge = f: f':
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let wrapped = f.wrapped.typeMerge f'.wrapped.functor;
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payload = f.binOp f.payload f'.payload;
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in
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# cannot merge different types
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if f.name != f'.name
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then null
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# simple types
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else if (f.wrapped == null && f'.wrapped == null)
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&& (f.payload == null && f'.payload == null)
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then f.type
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# composed types
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else if (f.wrapped != null && f'.wrapped != null) && (wrapped != null)
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then f.type wrapped
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# value types
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else if (f.payload != null && f'.payload != null) && (payload != null)
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then f.type payload
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else null;
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# Default type functor
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defaultFunctor = name: {
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inherit name;
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type = types."${name}" or null;
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wrapped = null;
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payload = null;
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binOp = a: b: null;
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};
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isOptionType = isType "option-type";
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mkOptionType =
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{ # Human-readable representation of the type, should be equivalent to
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# the type function name.
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name
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, # Description of the type, defined recursively by embedding the wrapped type if any.
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description ? null
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, # Function applied to each definition that should return true if
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# its type-correct, false otherwise.
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check ? (x: true)
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, # Merge a list of definitions together into a single value.
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# This function is called with two arguments: the location of
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# the option in the configuration as a list of strings
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# (e.g. ["boot" "loader "grub" "enable"]), and a list of
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# definition values and locations (e.g. [ { file = "/foo.nix";
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# value = 1; } { file = "/bar.nix"; value = 2 } ]).
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merge ? mergeDefaultOption
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, # Return a flat list of sub-options. Used to generate
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# documentation.
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getSubOptions ? prefix: {}
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, # List of modules if any, or null if none.
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getSubModules ? null
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, # Function for building the same option type with a different list of
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# modules.
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substSubModules ? m: null
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, # Function that merge type declarations.
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# internal, takes a functor as argument and returns the merged type.
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# returning null means the type is not mergeable
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typeMerge ? defaultTypeMerge functor
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, # The type functor.
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# internal, representation of the type as an attribute set.
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# name: name of the type
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# type: type function.
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# wrapped: the type wrapped in case of compound types.
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# payload: values of the type, two payloads of the same type must be
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# combinable with the binOp binary operation.
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# binOp: binary operation that merge two payloads of the same type.
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functor ? defaultFunctor name
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}:
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{ _type = "option-type";
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inherit name check merge getSubOptions getSubModules substSubModules typeMerge functor;
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description = if description == null then name else description;
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};
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# When adding new types don't forget to document them in
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# nixos/doc/manual/development/option-types.xml!
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types = rec {
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unspecified = mkOptionType {
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name = "unspecified";
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};
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bool = mkOptionType {
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name = "bool";
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description = "boolean";
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check = isBool;
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merge = mergeEqualOption;
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};
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int = mkOptionType rec {
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name = "int";
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description = "integer";
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check = isInt;
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merge = mergeOneOption;
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};
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str = mkOptionType {
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name = "str";
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description = "string";
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check = isString;
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merge = mergeOneOption;
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};
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# Merge multiple definitions by concatenating them (with the given
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# separator between the values).
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separatedString = sep: mkOptionType rec {
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name = "separatedString";
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description = "string";
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check = isString;
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merge = loc: defs: concatStringsSep sep (getValues defs);
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functor = (defaultFunctor name) // {
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payload = sep;
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binOp = sepLhs: sepRhs:
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if sepLhs == sepRhs then sepLhs
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else null;
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};
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};
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lines = separatedString "\n";
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commas = separatedString ",";
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envVar = separatedString ":";
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# Deprecated; should not be used because it quietly concatenates
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# strings, which is usually not what you want.
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string = separatedString "";
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attrs = mkOptionType {
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name = "attrs";
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description = "attribute set";
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check = isAttrs;
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merge = loc: foldl' (res: def: mergeAttrs res def.value) {};
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};
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# derivation is a reserved keyword.
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package = mkOptionType {
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name = "package";
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check = x: isDerivation x || isStorePath x;
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merge = loc: defs:
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let res = mergeOneOption loc defs;
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in if isDerivation res then res else toDerivation res;
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};
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shellPackage = package // {
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check = x: (package.check x) && (hasAttr "shellPath" x);
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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 = x: builtins.substring 0 1 (toString x) == "/";
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merge = mergeOneOption;
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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 rec {
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name = "listOf";
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description = "list of ${elemType.description}s";
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check = isList;
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merge = loc: defs:
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map (x: x.value) (filter (x: x ? value) (concatLists (imap (n: def:
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if isList def.value then
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imap (m: def':
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(mergeDefinitions
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(loc ++ ["[definition ${toString n}-entry ${toString m}]"])
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elemType
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[{ inherit (def) file; value = def'; }]
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).optionalValue
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) def.value
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else
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throw "The option value `${showOption loc}' in `${def.file}' is not a list.") defs)));
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getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
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getSubModules = elemType.getSubModules;
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substSubModules = m: listOf (elemType.substSubModules m);
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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attrsOf = elemType: mkOptionType rec {
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name = "attrsOf";
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description = "attribute set of ${elemType.description}s";
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check = isAttrs;
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merge = loc: defs:
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mapAttrs (n: v: v.value) (filterAttrs (n: v: v ? value) (zipAttrsWith (name: defs:
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(mergeDefinitions (loc ++ [name]) elemType defs).optionalValue
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)
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# Push down position info.
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(map (def: listToAttrs (mapAttrsToList (n: def':
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{ name = n; value = { inherit (def) file; value = def'; }; }) def.value)) defs)));
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getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
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getSubModules = elemType.getSubModules;
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substSubModules = m: attrsOf (elemType.substSubModules m);
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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# List or attribute set of ...
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loaOf = elemType:
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let
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convertIfList = defIdx: def:
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if isList def.value then
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{ inherit (def) file;
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value = listToAttrs (
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imap (elemIdx: elem:
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{ name = elem.name or "unnamed-${toString defIdx}.${toString elemIdx}";
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value = elem;
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}) def.value);
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}
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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 rec {
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name = "loaOf";
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description = "list or attribute set of ${elemType.description}s";
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check = x: isList x || isAttrs x;
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merge = loc: defs: attrOnly.merge loc (imap convertIfList defs);
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getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
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getSubModules = elemType.getSubModules;
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substSubModules = m: loaOf (elemType.substSubModules m);
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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# List or element of ...
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loeOf = elemType: mkOptionType rec {
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name = "loeOf";
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description = "element or list of ${elemType.description}s";
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check = x: isList x || elemType.check x;
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merge = loc: defs:
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let
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defs' = filterOverrides defs;
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res = (head defs').value;
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in
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if isList res then concatLists (getValues defs')
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else if lessThan 1 (length defs') then
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throw "The option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
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else if !isString res then
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throw "The option `${showOption loc}' does not have a string value, in ${showFiles (getFiles defs)}."
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else res;
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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# Value of given type but with no merging (i.e. `uniq list`s are not concatenated).
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uniq = elemType: mkOptionType rec {
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name = "uniq";
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inherit (elemType) description check;
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merge = mergeOneOption;
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getSubOptions = elemType.getSubOptions;
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getSubModules = elemType.getSubModules;
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substSubModules = m: uniq (elemType.substSubModules m);
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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# Null or value of ...
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nullOr = elemType: mkOptionType rec {
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name = "nullOr";
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description = "null or ${elemType.description}";
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check = x: x == null || elemType.check x;
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merge = loc: defs:
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let nrNulls = count (def: def.value == null) defs; in
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if nrNulls == length defs then null
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else if nrNulls != 0 then
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throw "The option `${showOption loc}' is defined both null and not null, in ${showFiles (getFiles defs)}."
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else elemType.merge loc defs;
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getSubOptions = elemType.getSubOptions;
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getSubModules = elemType.getSubModules;
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substSubModules = m: nullOr (elemType.substSubModules m);
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functor = (defaultFunctor name) // { wrapped = elemType; };
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};
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# A submodule (like typed attribute set). See NixOS manual.
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submodule = opts:
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let
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opts' = toList opts;
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inherit (import ./modules.nix) evalModules;
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in
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mkOptionType rec {
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name = "submodule";
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check = x: isAttrs x || isFunction x;
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merge = loc: defs:
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let
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coerce = def: if isFunction def then def else { config = def; };
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modules = opts' ++ map (def: { _file = def.file; imports = [(coerce def.value)]; }) defs;
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in (evalModules {
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inherit modules;
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args.name = last loc;
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prefix = loc;
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}).config;
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getSubOptions = prefix: (evalModules
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{ modules = opts'; inherit prefix;
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# FIXME: hack to get shit to evaluate.
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args = { name = ""; }; }).options;
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getSubModules = opts';
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substSubModules = m: submodule m;
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functor = (defaultFunctor name) // {
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# Merging of submodules is done as part of mergeOptionDecls, as we have to annotate
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# each submodule with its location.
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payload = [];
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binOp = lhs: rhs: [];
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};
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};
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# A value from a set of allowed ones.
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enum = values:
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let
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show = v:
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if builtins.isString v then ''"${v}"''
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else if builtins.isInt v then builtins.toString v
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else ''<${builtins.typeOf v}>'';
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in
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mkOptionType rec {
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name = "enum";
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description = "one of ${concatMapStringsSep ", " show values}";
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check = flip elem values;
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merge = mergeOneOption;
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functor = (defaultFunctor name) // { payload = values; binOp = a: b: unique (a ++ b); };
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};
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# Either value of type `t1` or `t2`.
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either = t1: t2: mkOptionType rec {
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name = "either";
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description = "${t1.description} or ${t2.description}";
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check = x: t1.check x || t2.check x;
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merge = loc: defs:
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let
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defList = map (d: d.value) defs;
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in
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if all (x: t1.check x) defList
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then t1.merge loc defs
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else if all (x: t2.check x) defList
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then t2.merge loc defs
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else mergeOneOption loc defs;
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typeMerge = f':
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let mt1 = t1.typeMerge (elemAt f'.wrapped 0).functor;
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mt2 = t2.typeMerge (elemAt f'.wrapped 1).functor;
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in
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if (name == f'.name) && (mt1 != null) && (mt2 != null)
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then functor.type mt1 mt2
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else null;
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functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
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};
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# Either value of type `finalType` or `coercedType`, the latter is
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# converted to `finalType` using `coerceFunc`.
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coercedTo = coercedType: coerceFunc: finalType:
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assert coercedType.getSubModules == null;
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mkOptionType rec {
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name = "coercedTo";
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description = "${finalType.description} or ${coercedType.description}";
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check = x: finalType.check x || coercedType.check x;
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merge = loc: defs:
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let
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coerceVal = val:
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if finalType.check val then val
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else let
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coerced = coerceFunc val;
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in assert finalType.check coerced; coerced;
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in finalType.merge loc (map (def: def // { value = coerceVal def.value; }) defs);
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getSubOptions = finalType.getSubOptions;
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getSubModules = finalType.getSubModules;
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substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
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typeMerge = t1: t2: null;
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functor = (defaultFunctor name) // { wrapped = finalType; };
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};
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# Obsolete alternative to configOf. It takes its option
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# declarations from the ‘options’ attribute of containing option
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# declaration.
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optionSet = mkOptionType {
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name = builtins.trace "types.optionSet is deprecated; use types.submodule instead" "optionSet";
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description = "option set";
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};
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# Augment the given type with an additional type check function.
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addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
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};
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}
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