forked from mirrors/nixpkgs
121 lines
4.6 KiB
Nix
121 lines
4.6 KiB
Nix
# Nixpkgs/NixOS option handling.
|
||
|
||
let lib = import ./default.nix; in
|
||
|
||
with import ./trivial.nix;
|
||
with import ./lists.nix;
|
||
with import ./misc.nix;
|
||
with import ./attrsets.nix;
|
||
with import ./strings.nix;
|
||
|
||
rec {
|
||
|
||
isOption = lib.isType "option";
|
||
mkOption =
|
||
{ default ? null # Default value used when no definition is given in the configuration.
|
||
, defaultText ? null # Textual representation of the default, for in the manual.
|
||
, example ? null # Example value used in the manual.
|
||
, description ? null # String describing the option.
|
||
, type ? null # Option type, providing type-checking and value merging.
|
||
, apply ? null # Function that converts the option value to something else.
|
||
, internal ? null # Whether the option is for NixOS developers only.
|
||
, visible ? null # Whether the option shows up in the manual.
|
||
, options ? null # Obsolete, used by types.optionSet.
|
||
} @ attrs:
|
||
attrs // { _type = "option"; };
|
||
|
||
mkEnableOption = name: mkOption {
|
||
default = false;
|
||
example = true;
|
||
description = "Whether to enable ${name}.";
|
||
type = lib.types.bool;
|
||
};
|
||
|
||
mergeDefaultOption = loc: defs:
|
||
let list = getValues defs; in
|
||
if length list == 1 then head list
|
||
else if all isFunction list then x: mergeDefaultOption loc (map (f: f x) list)
|
||
else if all isList list then concatLists list
|
||
else if all isAttrs list then fold lib.mergeAttrs {} list
|
||
else if all isBool list then fold lib.or false list
|
||
else if all isString list then lib.concatStrings list
|
||
else if all isInt list && all (x: x == head list) list then head list
|
||
else throw "Cannot merge definitions of `${showOption loc}' given in ${showFiles (getFiles defs)}.";
|
||
|
||
/* Obsolete, will remove soon. Specify an option type or apply
|
||
function instead. */
|
||
mergeTypedOption = typeName: predicate: merge: loc: list:
|
||
let list' = map (x: x.value) list; in
|
||
if all predicate list then merge list'
|
||
else throw "Expected a ${typeName}.";
|
||
|
||
mergeEnableOption = mergeTypedOption "boolean"
|
||
(x: true == x || false == x) (fold lib.or false);
|
||
|
||
mergeListOption = mergeTypedOption "list" isList concatLists;
|
||
|
||
mergeStringOption = mergeTypedOption "string" isString lib.concatStrings;
|
||
|
||
mergeOneOption = loc: defs:
|
||
if defs == [] then abort "This case should never happen."
|
||
else if length defs != 1 then
|
||
throw "The unique option `${showOption loc}' is defined multiple times, in ${showFiles (getFiles defs)}."
|
||
else (head defs).value;
|
||
|
||
getValues = map (x: x.value);
|
||
getFiles = map (x: x.file);
|
||
|
||
|
||
# Generate documentation template from the list of option declaration like
|
||
# the set generated with filterOptionSets.
|
||
optionAttrSetToDocList = optionAttrSetToDocList' [];
|
||
|
||
optionAttrSetToDocList' = prefix: options:
|
||
fold (opt: rest:
|
||
let
|
||
docOption = rec {
|
||
name = showOption opt.loc;
|
||
description = opt.description or (throw "Option `${name}' has no description.");
|
||
declarations = filter (x: x != unknownModule) opt.declarations;
|
||
internal = opt.internal or false;
|
||
visible = opt.visible or true;
|
||
}
|
||
// optionalAttrs (opt ? example) { example = scrubOptionValue opt.example; }
|
||
// optionalAttrs (opt ? default) { default = scrubOptionValue opt.default; }
|
||
// optionalAttrs (opt ? defaultText) { default = opt.defaultText; };
|
||
|
||
subOptions =
|
||
let ss = opt.type.getSubOptions opt.loc;
|
||
in if ss != {} then optionAttrSetToDocList' opt.loc ss else [];
|
||
in
|
||
# FIXME: expensive, O(n^2)
|
||
[ docOption ] ++ subOptions ++ rest) [] (collect isOption options);
|
||
|
||
|
||
/* This function recursively removes all derivation attributes from
|
||
`x' except for the `name' attribute. This is to make the
|
||
generation of `options.xml' much more efficient: the XML
|
||
representation of derivations is very large (on the order of
|
||
megabytes) and is not actually used by the manual generator. */
|
||
scrubOptionValue = x:
|
||
if isDerivation x then
|
||
{ type = "derivation"; drvPath = x.name; outPath = x.name; name = x.name; }
|
||
else if isList x then map scrubOptionValue x
|
||
else if isAttrs x then mapAttrs (n: v: scrubOptionValue v) (removeAttrs x ["_args"])
|
||
else x;
|
||
|
||
|
||
/* For use in the ‘example’ option attribute. It causes the given
|
||
text to be included verbatim in documentation. This is necessary
|
||
for example values that are not simple values, e.g.,
|
||
functions. */
|
||
literalExample = text: { _type = "literalExample"; inherit text; };
|
||
|
||
|
||
/* Helper functions. */
|
||
showOption = concatStringsSep ".";
|
||
showFiles = files: concatStringsSep " and " (map (f: "`${f}'") files);
|
||
unknownModule = "<unknown-file>";
|
||
|
||
}
|