nixpkgs/lib/types.nix

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# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
with import ./lists.nix;
with import ./attrsets.nix;
with import ./options.nix;
with import ./trivial.nix;
with import ./strings.nix;
with {inherit (import ./modules.nix) mergeDefinitions filterOverrides; };
rec {
isType = type: x: (x._type or "") == type;
setType = typeName: value: value // {
_type = typeName;
};
isOptionType = isType "option-type";
mkOptionType =
{ # Human-readable representation of the type.
name
, # Function applied to each definition that should return true if
# its type-correct, false otherwise.
check ? (x: true)
, # Merge a list of definitions together into a single value.
# This function is called with two arguments: the location of
# the option in the configuration as a list of strings
# (e.g. ["boot" "loader "grub" "enable"]), and a list of
# definition values and locations (e.g. [ { file = "/foo.nix";
# value = 1; } { file = "/bar.nix"; value = 2 } ]).
merge ? mergeDefaultOption
, # Return a flat list of sub-options. Used to generate
# documentation.
getSubOptions ? prefix: {}
, # List of modules if any, or null if none.
getSubModules ? null
, # Function for building the same option type with a different list of
# modules.
substSubModules ? m: null
}:
{ _type = "option-type";
inherit name check merge getSubOptions getSubModules substSubModules;
};
types = rec {
unspecified = mkOptionType {
name = "unspecified";
};
bool = mkOptionType {
name = "boolean";
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check = isBool;
merge = mergeEqualOption;
};
int = mkOptionType {
name = "integer";
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check = isInt;
merge = mergeOneOption;
};
str = mkOptionType {
name = "string";
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check = isString;
merge = mergeOneOption;
};
# Merge multiple definitions by concatenating them (with the given
# separator between the values).
separatedString = sep: mkOptionType {
name = "string";
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check = isString;
merge = loc: defs: concatStringsSep sep (getValues defs);
};
lines = separatedString "\n";
commas = separatedString ",";
envVar = separatedString ":";
# Deprecated; should not be used because it quietly concatenates
# strings, which is usually not what you want.
string = separatedString "";
attrs = mkOptionType {
name = "attribute set";
check = isAttrs;
merge = loc: foldl' (res: def: mergeAttrs res def.value) {};
};
# derivation is a reserved keyword.
package = mkOptionType {
lib/types: Set name of types.package to "package" Nobody seems to have noticed this (except @Profpatsch) that options with a "package" type do not get included in the manual. So debugging this was a bit more involving because while generating the manual there is an optionList' attribute built from the collected attributes of all the option declarations. Up to that point everything is fine except if it comes to builtins.toXML, where attributes with { type = "derivation" } won't get included, for example see here: nix-repl> builtins.toXML { type = "derivation"; foo = "bar"; } "<?xml version='1.0' encoding='utf-8'?>\n<expr>\n <derivation> <repeated />\n </derivation>\n</expr>\n" nix-repl> builtins.toXML { type = "somethingelse"; foo = "bar"; } "<?xml version='1.0' encoding='utf-8'?>\n<expr>\n <attrs> <attr name=\"foo\">\n <string value=\"bar\" />\n </attr> <attr name=\"type\">\n <string value=\"somethingelse\" /> </attr>\n </attrs>\n</expr>\n" The following function in libexpr/eval.cc (Nix) is responsible for toXML dropping the attributes: bool EvalState::isDerivation(Value & v) { if (v.type != tAttrs) return false; Bindings::iterator i = v.attrs->find(sType); if (i == v.attrs->end()) return false; forceValue(*i->value); if (i->value->type != tString) return false; return strcmp(i->value->string.s, "derivation") == 0; } So I've renamed this now to "package" which is not only more consistent with the option type but also shouldn't cause similar issues anymore. Tested this on base of b60ceea, because building the dependencies on recent libc/staging changes on master took too long. Signed-off-by: aszlig <aszlig@redmoonstudios.org> Reported-by: Profpatsch <mail@profpatsch.de>
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name = "package";
check = x: isDerivation x || isStorePath x;
merge = loc: defs:
let res = mergeOneOption loc defs;
in if isDerivation res then res else toDerivation res;
};
path = mkOptionType {
name = "path";
# Hacky: there is no isPath primop.
check = x: builtins.substring 0 1 (toString x) == "/";
merge = mergeOneOption;
};
# drop this in the future:
list = builtins.trace "`types.list' is deprecated; use `types.listOf' instead" types.listOf;
listOf = elemType: mkOptionType {
name = "list of ${elemType.name}s";
check = isList;
merge = loc: defs:
map (x: x.value) (filter (x: x ? value) (concatLists (imap (n: def:
if isList def.value then
imap (m: def':
(mergeDefinitions
(loc ++ ["[definition ${toString n}-entry ${toString m}]"])
elemType
[{ inherit (def) file; value = def'; }]
).optionalValue
) def.value
else
throw "The option value `${showOption loc}' in `${def.file}' is not a list.") defs)));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
getSubModules = elemType.getSubModules;
substSubModules = m: listOf (elemType.substSubModules m);
};
attrsOf = elemType: mkOptionType {
name = "attribute set of ${elemType.name}s";
check = isAttrs;
merge = loc: defs:
mapAttrs (n: v: v.value) (filterAttrs (n: v: v ? value) (zipAttrsWith (name: defs:
(mergeDefinitions (loc ++ [name]) elemType defs).optionalValue
)
# Push down position info.
(map (def: listToAttrs (mapAttrsToList (n: def':
{ name = n; value = { inherit (def) file; value = def'; }; }) def.value)) defs)));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: attrsOf (elemType.substSubModules m);
};
# List or attribute set of ...
loaOf = elemType:
let
convertIfList = defIdx: def:
if isList def.value then
{ inherit (def) file;
value = listToAttrs (
imap (elemIdx: elem:
{ name = elem.name or "unnamed-${toString defIdx}.${toString elemIdx}";
value = elem;
}) def.value);
}
else
def;
listOnly = listOf elemType;
attrOnly = attrsOf elemType;
in mkOptionType {
name = "list or attribute set of ${elemType.name}s";
check = x: isList x || isAttrs x;
merge = loc: defs: attrOnly.merge loc (imap convertIfList defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
getSubModules = elemType.getSubModules;
substSubModules = m: loaOf (elemType.substSubModules m);
};
# List or element of ...
loeOf = elemType: mkOptionType {
name = "element or list of ${elemType.name}s";
check = x: isList x || elemType.check x;
merge = loc: defs:
let
defs' = filterOverrides defs;
res = (head defs').value;
in
if isList res then concatLists (getValues defs')
else if lessThan 1 (length defs') then
throw "The option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
else if !isString res then
throw "The option `${showOption loc}' does not have a string value, in ${showFiles (getFiles defs)}."
else res;
};
uniq = elemType: mkOptionType {
inherit (elemType) name check;
merge = mergeOneOption;
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getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: uniq (elemType.substSubModules m);
};
nullOr = elemType: mkOptionType {
name = "null or ${elemType.name}";
check = x: x == null || elemType.check x;
merge = loc: defs:
let nrNulls = count (def: def.value == null) defs; in
if nrNulls == length defs then null
else if nrNulls != 0 then
throw "The option `${showOption loc}' is defined both null and not null, in ${showFiles (getFiles defs)}."
else elemType.merge loc defs;
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getSubOptions = elemType.getSubOptions;
getSubModules = elemType.getSubModules;
substSubModules = m: nullOr (elemType.substSubModules m);
};
submodule = opts:
let
opts' = toList opts;
inherit (import ./modules.nix) evalModules;
in
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mkOptionType rec {
name = "submodule";
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check = x: isAttrs x || isFunction x;
merge = loc: defs:
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let
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coerce = def: if isFunction def then def else { config = def; };
modules = opts' ++ map (def: { _file = def.file; imports = [(coerce def.value)]; }) defs;
in (evalModules {
inherit modules;
args.name = last loc;
prefix = loc;
}).config;
getSubOptions = prefix: (evalModules
{ modules = opts'; inherit prefix;
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# FIXME: hack to get shit to evaluate.
args = { name = ""; }; }).options;
getSubModules = opts';
substSubModules = m: submodule m;
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};
enum = values:
let
show = v:
if builtins.isString v then ''"${v}"''
else if builtins.isInt v then builtins.toString v
else ''<${builtins.typeOf v}>'';
in
mkOptionType {
name = "one of ${concatMapStringsSep ", " show values}";
check = flip elem values;
merge = mergeOneOption;
};
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either = t1: t2: mkOptionType {
name = "${t1.name} or ${t2.name}";
check = x: t1.check x || t2.check x;
merge = mergeOneOption;
};
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# Obsolete alternative to configOf. It takes its option
# declarations from the options attribute of containing option
# declaration.
optionSet = mkOptionType {
name = /* builtins.trace "types.optionSet is deprecated; use types.submodule instead" */ "option set";
};
# Augment the given type with an additional type check function.
addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
};
}