a440fba8e3
big. Also, they could be useful beyond option handling. svn path=/nixpkgs/trunk/; revision=16055
761 lines
24 KiB
Nix
761 lines
24 KiB
Nix
# Nixpkgs/NixOS option handling.
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let lib = import ./default.nix; in
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with { inherit (builtins) head tail; };
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with import ./trivial.nix;
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with import ./lists.nix;
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with import ./misc.nix;
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with import ./attrsets.nix;
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rec {
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inherit (lib) typeOf;
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isOption = attrs: (typeOf attrs) == "option";
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mkOption = attrs: attrs // {
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_type = "option";
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# name (this is the name of the attributem it is automatically generated by the traversal)
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# default (value used when no definition exists)
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# example (documentation)
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# description (documentation)
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# type (option type, provide a default merge function and ensure type correctness)
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# merge (function used to merge definitions into one definition: [ /type/ ] -> /type/)
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# apply (convert the option value to ease the manipulation of the option result)
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# options (set of sub-options declarations & definitions)
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};
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# Make the option declaration more user-friendly by adding default
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# settings and some verifications based on the declaration content (like
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# type correctness).
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addOptionMakeUp = {name, recurseInto}: decl:
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let
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init = {
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inherit name;
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merge = mergeDefaultOption;
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apply = lib.id;
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};
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mergeFromType = opt:
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if decl ? type && decl.type ? merge then
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opt // { merge = decl.type.merge; }
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else
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opt;
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addDeclaration = opt: opt // decl;
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ensureMergeInputType = opt:
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if decl ? type then
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opt // {
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merge = list:
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if all decl.type.check list then
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opt.merge list
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else
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throw "One of the definitions has a bad type.";
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}
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else opt;
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ensureDefaultType = opt:
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if decl ? type && decl ? default then
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opt // {
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default =
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if decl.type.check decl.default then
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decl.default
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else
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throw "The default value has a bad type.";
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}
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else opt;
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handleOptionSets = opt:
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if decl ? type && decl.type.hasOptions then
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let
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optionConfig = opts: config:
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map (f: applyIfFunction f config)
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(decl.options ++ [opts]);
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in
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opt // {
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merge = list:
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decl.type.iter
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(path: opts:
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fixMergeFun (recurseInto path) (optionConfig opts)
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)
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opt.name
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(opt.merge list);
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options = recurseInto (decl.type.docPath opt.name) decl.options;
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}
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else
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opt;
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in
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foldl (opt: f: f opt) init [
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# default settings
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mergeFromType
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# user settings
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addDeclaration
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# override settings
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ensureMergeInputType
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ensureDefaultType
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handleOptionSets
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];
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# Merge a list of options containning different field. This is useful to
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# separate the merge & apply fields from the interface.
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mergeOptionDecls = opts:
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if opts == [] then {}
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else if tail opts == [] then
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let opt = head opts; in
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if opt ? options then
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opt // { options = toList opt.options; }
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else
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opt
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else
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fold (opt1: opt2:
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lib.addErrorContext "opt1 = ${lib.showVal opt1}\nopt2 = ${lib.showVal opt2}" (
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# You cannot merge if two options have the same field.
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assert opt1 ? default -> ! opt2 ? default;
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assert opt1 ? example -> ! opt2 ? example;
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assert opt1 ? description -> ! opt2 ? description;
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assert opt1 ? merge -> ! opt2 ? merge;
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assert opt1 ? apply -> ! opt2 ? apply;
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assert opt1 ? type -> ! opt2 ? type;
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if opt1 ? options || opt2 ? options then
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opt1 // opt2 // {
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options =
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(toList (attrByPath ["options"] [] opt1))
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++ (toList (attrByPath ["options"] [] opt2));
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}
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else
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opt1 // opt2
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)) {} opts;
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# !!! This function will be removed because this can be done with the
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# multiple option declarations.
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addDefaultOptionValues = defs: opts: opts //
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builtins.listToAttrs (map (defName:
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{ name = defName;
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value =
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let
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defValue = builtins.getAttr defName defs;
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optValue = builtins.getAttr defName opts;
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in
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if typeOf defValue == "option"
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then
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# `defValue' is an option.
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if hasAttr defName opts
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then builtins.getAttr defName opts
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else defValue.default
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else
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# `defValue' is an attribute set containing options.
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# So recurse.
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if hasAttr defName opts && isAttrs optValue
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then addDefaultOptionValues defValue optValue
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else addDefaultOptionValues defValue {};
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}
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) (attrNames defs));
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mergeDefaultOption = list:
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if list != [] && tail list == [] then head list
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else if all builtins.isFunction list then x: mergeDefaultOption (map (f: f x) list)
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else if all isList list then concatLists list
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else if all isAttrs list then fold lib.mergeAttrs {} list
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else if all (x: true == x || false == x) list then fold lib.or false list
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else if all (x: x == toString x) list then lib.concatStrings list
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else throw "Cannot merge values.";
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mergeTypedOption = typeName: predicate: merge: list:
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if all predicate list then merge list
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else throw "Expect a ${typeName}.";
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mergeEnableOption = mergeTypedOption "boolean"
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(x: true == x || false == x) (fold lib.or false);
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mergeListOption = mergeTypedOption "list" isList concatLists;
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mergeStringOption = mergeTypedOption "string"
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(x: if builtins ? isString then builtins.isString x else x + "")
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lib.concatStrings;
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mergeOneOption = list:
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if list == [] then abort "This case should never happen."
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else if tail list != [] then throw "Multiple definitions. Only one is allowed for this option."
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else head list;
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# Handle the traversal of option sets. All sets inside 'opts' are zipped
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# and options declaration and definition are separated. If no option are
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# declared at a specific depth, then the function recurse into the values.
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# Other cases are handled by the optionHandler which contains two
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# functions that are used to defined your goal.
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# - export is a function which takes two arguments which are the option
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# and the list of values.
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# - notHandle is a function which takes the list of values are not handle
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# by this function.
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handleOptionSets = optionHandler@{export, notHandle, ...}: path: opts:
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if all isAttrs opts then
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lib.zip (attr: opts:
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let
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recurseInto = name: attrs:
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handleOptionSets optionHandler name attrs;
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# Compute the path to reach the attribute.
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name = if path == "" then attr else path + "." + attr;
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# Divide the definitions of the attribute "attr" between
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# declaration (isOption) and definitions (!isOption).
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test = partition (x: isOption (rmProperties x)) opts;
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decls = map rmProperties test.right; defs = test.wrong;
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# Make the option declaration more user-friendly by adding default
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# settings and some verifications based on the declaration content
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# (like type correctness).
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opt = addOptionMakeUp
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{ inherit name recurseInto; }
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(mergeOptionDecls decls);
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# Return the list of option sets.
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optAttrs = map delayProperties defs;
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# return the list of option values.
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# Remove undefined values that are coming from evalIf.
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optValues = evalProperties defs;
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in
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if decls == [] then recurseInto name optAttrs
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else lib.addErrorContext "while evaluating the option ${name}:" (
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export opt optValues
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)
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) opts
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else lib.addErrorContext "while evaluating ${path}:" (notHandle opts);
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# Merge option sets and produce a set of values which is the merging of
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# all options declare and defined. If no values are defined for an
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# option, then the default value is used otherwise it use the merge
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# function of each option to get the result.
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mergeOptionSets =
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handleOptionSets {
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export = opt: values:
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opt.apply (
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if values == [] then
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if opt ? default then opt.default
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else throw "Not defined."
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else opt.merge values
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);
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notHandle = opts: throw "Used without option declaration.";
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};
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# Keep all option declarations.
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filterOptionSets =
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handleOptionSets {
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export = opt: values: opt;
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notHandle = opts: {};
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};
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# Unfortunately this can also be a string.
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isPath = x: !(
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builtins.isFunction x
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|| builtins.isAttrs x
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|| builtins.isInt x
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|| builtins.isBool x
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|| builtins.isList x
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);
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applyIfFunction = f: arg:
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if builtins.isFunction f then
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f arg
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else
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f;
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moduleClosure = initModules: args:
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let
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moduleImport = path:
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(applyIfFunction (import path) args) // {
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# used by generic closure to avoid duplicated imports.
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key = path;
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};
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in
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builtins.genericClosure {
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startSet = map moduleImport initModules;
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operator = m:
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map moduleImport (attrByPath ["imports"] [] m);
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};
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selectDeclsAndDefs = modules:
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lib.concatMap (m:
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attrByPath ["options"] [] m
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++ attrByPath ["config"] [] m
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) modules;
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fixMergeFun = merge: optFun:
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lib.fix (config:
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merge (
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# Delay top-level properties like mkIf
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map delayProperties (
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# generate the list of option sets.
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optFun config
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)
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)
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);
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fixMergeModules = merge: initModules: {...}@args:
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fixMergeFun (config:
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selectDeclsAndDefs (
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moduleClosure initModules (args // { inherit config; })
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)
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);
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fixModulesConfig = initModules: {...}@args:
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fixMergeModules (mergeOptionSets "") initModules args;
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fixOptionsConfig = initModules: {...}@args:
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fixMergeModules (filterOptionSets "") initModules args;
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# Evaluate a list of option sets that would be merged with the
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# function "merge" which expects two arguments. The attribute named
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# "require" is used to imports option declarations and bindings.
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#
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# * cfg[0-9]: configuration
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# * cfgSet[0-9]: configuration set
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#
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# merge: the function used to merge options sets.
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# pkgs: is the set of packages available. (nixpkgs)
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# opts: list of option sets or option set functions.
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# config: result of this evaluation.
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fixOptionSetsFun = merge: pkgs: opts: config:
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let
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# remove possible mkIf to access the require attribute.
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noImportConditions = cfgSet0:
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let cfgSet1 = delayProperties cfgSet0; in
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if cfgSet1 ? require then
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cfgSet1 // { require = rmProperties cfgSet1.require; }
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else
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cfgSet1;
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filenameHandler = cfg:
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if isPath cfg then import cfg
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else cfg;
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# call configuration "files" with one of the existing convention.
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argumentHandler = cfg:
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let
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# {..}
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cfg0 = cfg;
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# {pkgs, config, ...}: {..}
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cfg1 = cfg { inherit pkgs config merge; };
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# pkgs: config: {..}
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cfg2 = cfg {} {};
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in
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if builtins.isFunction cfg0 then
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if isAttrs cfg1 then cfg1
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else builtins.trace "Use '{pkgs, config, ...}:'." cfg2
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else cfg0;
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preprocess = cfg0:
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let cfg1 = filenameHandler cfg0;
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cfg2 = argumentHandler cfg1;
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cfg3 = noImportConditions cfg2;
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in cfg3;
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getRequire = x: toList (attrByPath ["require"] [] (preprocess x));
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getRecursiveRequire = x:
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fold (cfg: l:
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if isPath cfg then
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[ cfg ] ++ l
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else
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[ cfg ] ++ (getRecursiveRequire cfg) ++ l
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) [] (getRequire x);
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getRequireSets = x: filter (x: ! isPath x) (getRecursiveRequire x);
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getRequirePaths = x: filter isPath (getRecursiveRequire x);
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rmRequire = x: removeAttrs (preprocess x) ["require"];
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inlineRequiredSets = cfgs:
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fold (cfg: l: [ cfg ] ++ (getRequireSets cfg) ++ l) [] cfgs;
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in
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merge "" (
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map rmRequire (
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inlineRequiredSets ((toList opts) ++ lib.uniqFlatten getRequirePaths [] [] (lib.concatMap getRequirePaths (toList opts)))
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)
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);
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fixOptionSets = merge: pkgs: opts:
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lib.fix (fixOptionSetsFun merge pkgs opts);
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# Generate documentation template from the list of option declaration like
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# the set generated with filterOptionSets.
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optionAttrSetToDocList = ignore: newOptionAttrSetToDocList;
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newOptionAttrSetToDocList = attrs:
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let options = collect isOption attrs; in
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fold (opt: rest:
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let
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docOption = {
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inherit (opt) name;
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description = if opt ? description then opt.description else
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throw "Option ${opt.name}: No description.";
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}
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// (if opt ? example then {inherit(opt) example;} else {})
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// (if opt ? default then {inherit(opt) default;} else {});
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subOptions =
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if opt ? options then
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newOptionAttrSetToDocList opt.options
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else
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[];
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in
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[ docOption ] ++ subOptions ++ rest
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) [] options;
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/* Option Properties */
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# Generalize the problem of delayable properties. Any property can be created
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# Tell that nothing is defined. When properties are evaluated, this type
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# is used to remove an entry. Thus if your property evaluation semantic
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# implies that you have to mute the content of an attribute, then your
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# property should produce this value.
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isNotdef = attrs: (typeOf attrs) == "notdef";
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mkNotdef = {_type = "notdef";};
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# General property type, it has a property attribute and a content
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# attribute. The property attribute refer to an attribute set which
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# contains a _type attribute and a list of functions which are used to
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# evaluate this property. The content attribute is used to stack property
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# on top of each other.
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#
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# The optional functions which may be contained in the property attribute
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# are:
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# - onDelay: run on a copied property.
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# - onGlobalDelay: run on all copied properties.
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# - onEval: run on an evaluated property.
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# - onGlobalEval: run on a list of property stack on top of their values.
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isProperty = attrs: (typeOf attrs) == "property";
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mkProperty = p@{property, content, ...}: p // {
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_type = "property";
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};
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# Go throw the stack of properties and apply the function `op' on all
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# property and call the function `nul' on the final value which is not a
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# property. The stack is traversed in reversed order. The `op' function
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# should expect a property with a content which have been modified.
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#
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# Warning: The `op' function expects only one argument in order to avoid
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# calls to mkProperties as the argument is already a valid property which
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# contains the result of the folding inside the content attribute.
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foldProperty = op: nul: attrs:
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if isProperty attrs then
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op (attrs // {
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content = foldProperty op nul attrs.content;
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})
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else
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nul attrs;
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# Simple function which can be used as the `op' argument of the
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# foldProperty function. Properties that you don't want to handle can be
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# ignored with the `id' function. `isSearched' is a function which should
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# check the type of a property and return a boolean value. `thenFun' and
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# `elseFun' are functions which behave as the `op' argument of the
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# foldProperty function.
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foldFilter = isSearched: thenFun: elseFun: attrs:
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if isSearched attrs.property then
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thenFun attrs
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else
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elseFun attrs;
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# Move properties from the current attribute set to the attribute
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# contained in this attribute set. This trigger property handlers called
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# `onDelay' and `onGlobalDelay'.
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delayProperties = attrs:
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let cleanAttrs = rmProperties attrs; in
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if isProperty attrs then
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lib.mapAttrs (a: v:
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lib.addErrorContext "while moving properties on the attribute `${a}'." (
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triggerPropertiesGlobalDelay a (
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triggerPropertiesDelay a (
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copyProperties attrs v
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)))) cleanAttrs
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else
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attrs;
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# Call onDelay functions.
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triggerPropertiesDelay = name: attrs:
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let
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callOnDelay = p@{property, ...}:
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lib.addErrorContext "while calling a onDelay function." (
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if property ? onDelay then
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property.onDelay name p
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else
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p
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);
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in
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foldProperty callOnDelay id attrs;
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# Call onGlobalDelay functions.
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triggerPropertiesGlobalDelay = name: attrs:
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let
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globalDelayFuns = uniqListExt {
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getter = property: property._type;
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inputList = foldProperty (p@{property, content, ...}:
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if property ? onGlobalDelay then
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[ property ] ++ content
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else
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content
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) (a: []) attrs;
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};
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callOnGlobalDelay = property: content:
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lib.addErrorContext "while calling a onGlobalDelay function." (
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property.onGlobalDelay name content
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);
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in
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fold callOnGlobalDelay attrs globalDelayFuns;
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# Expect a list of values which may have properties and return the same
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# list of values where all properties have been evaluated and where all
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# ignored values are removed. This trigger property handlers called
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# `onEval' and `onGlobalEval'.
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evalProperties = valList:
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if valList != [] then
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filter (x: !isNotdef x) (
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lib.addErrorContext "while evaluating properties an attribute." (
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triggerPropertiesGlobalEval (
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map triggerPropertiesEval valList
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)))
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else
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valList;
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# Call onEval function
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triggerPropertiesEval = val:
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foldProperty (p@{property, ...}:
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lib.addErrorContext "while calling a onEval function." (
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if property ? onEval then
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property.onEval p
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else
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p
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)
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) id val;
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# Call onGlobalEval function
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triggerPropertiesGlobalEval = valList:
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let
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globalEvalFuns = uniqListExt {
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getter = property: property._type;
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|
inputList =
|
|
fold (attrs: list:
|
|
foldProperty (p@{property, content, ...}:
|
|
if property ? onGlobalEval then
|
|
[ property ] ++ content
|
|
else
|
|
content
|
|
) (a: list) attrs
|
|
) [] valList;
|
|
};
|
|
|
|
callOnGlobalEval = property: valList:
|
|
lib.addErrorContext "while calling a onGlobalEval function." (
|
|
property.onGlobalEval valList
|
|
);
|
|
in
|
|
fold callOnGlobalEval valList globalEvalFuns;
|
|
|
|
# Remove all properties on top of a value and return the value.
|
|
rmProperties =
|
|
foldProperty (p@{content, ...}: content) id;
|
|
|
|
# Copy properties defined on a value on another value.
|
|
copyProperties = attrs: newAttrs:
|
|
foldProperty id (x: newAttrs) attrs;
|
|
|
|
/* If. ThenElse. Always. */
|
|
|
|
# create "if" statement that can be delayed on sets until a "then-else" or
|
|
# "always" set is reached. When an always set is reached the condition
|
|
# is ignore.
|
|
|
|
# Create a "If" property which only contains a condition.
|
|
isIf = attrs: (typeOf attrs) == "if";
|
|
mkIf = condition: content: mkProperty {
|
|
property = {
|
|
_type = "if";
|
|
onGlobalDelay = onIfGlobalDelay;
|
|
onEval = onIfEval;
|
|
inherit condition;
|
|
};
|
|
inherit content;
|
|
};
|
|
|
|
# Create a "ThenElse" property which contains choices which can choosed by
|
|
# the evaluation of an "If" statement.
|
|
isThenElse = attrs: (typeOf attrs) == "then-else";
|
|
mkThenElse = attrs:
|
|
assert attrs ? thenPart && attrs ? elsePart;
|
|
mkProperty {
|
|
property = {
|
|
_type = "then-else";
|
|
onEval = val: throw "Missing mkIf statement.";
|
|
inherit (attrs) thenPart elsePart;
|
|
};
|
|
content = mkNotdef;
|
|
};
|
|
|
|
# Create an "Always" property remove ignore all "If" statement.
|
|
isAlways = attrs: (typeOf attrs) == "always";
|
|
mkAlways = value:
|
|
mkProperty {
|
|
property = {
|
|
_type = "always";
|
|
onEval = p@{content, ...}: content;
|
|
inherit value;
|
|
};
|
|
content = mkNotdef;
|
|
};
|
|
|
|
# Remove all "If" statement defined on a value.
|
|
rmIf = foldProperty (
|
|
foldFilter isIf
|
|
({content, ...}: content)
|
|
id
|
|
) id;
|
|
|
|
# Evaluate the "If" statements when either "ThenElse" or "Always"
|
|
# statement is encounter. Otherwise it remove multiple If statement and
|
|
# replace them by one "If" staement where the condition is the list of all
|
|
# conditions joined with a "and" operation.
|
|
onIfGlobalDelay = name: content:
|
|
let
|
|
# extract if statements and non-if statements and repectively put them
|
|
# in the attribute list and attrs.
|
|
ifProps =
|
|
foldProperty
|
|
(foldFilter (p: isIf p || isThenElse p || isAlways p)
|
|
# then, push the codition inside the list list
|
|
(p@{property, content, ...}:
|
|
{ inherit (content) attrs;
|
|
list = [property] ++ content.list;
|
|
}
|
|
)
|
|
# otherwise, add the propertie.
|
|
(p@{property, content, ...}:
|
|
{ inherit (content) list;
|
|
attrs = p // { content = content.attrs; };
|
|
}
|
|
)
|
|
)
|
|
(attrs: { list = []; inherit attrs; })
|
|
content;
|
|
|
|
# compute the list of if statements.
|
|
evalIf = content: condition: list:
|
|
if list == [] then
|
|
mkIf condition content
|
|
else
|
|
let p = head list; in
|
|
|
|
# evaluate the condition.
|
|
if isThenElse p then
|
|
if condition then
|
|
copyProperties content p.thenPart
|
|
else
|
|
copyProperties content p.elsePart
|
|
# ignore the condition.
|
|
else if isAlways p then
|
|
copyProperties content p.value
|
|
# otherwise (isIf)
|
|
else
|
|
evalIf content (condition && p.condition) (tail list);
|
|
in
|
|
evalIf ifProps.attrs true ifProps.list;
|
|
|
|
# Evaluate the condition of the "If" statement to either get the value or
|
|
# to ignore the value.
|
|
onIfEval = p@{property, content, ...}:
|
|
if property.condition then
|
|
content
|
|
else
|
|
mkNotdef;
|
|
|
|
/* mkOverride */
|
|
|
|
# Create an "Override" statement which allow the user to define
|
|
# prioprities between values. The default priority is 100 and the lowest
|
|
# priorities are kept. The template argument must reproduce the same
|
|
# attribute set hierachy to override leaves of the hierarchy.
|
|
isOverride = attrs: (typeOf attrs) == "override";
|
|
mkOverride = priority: template: content: mkProperty {
|
|
property = {
|
|
_type = "override";
|
|
onDelay = onOverrideDelay;
|
|
onGlobalEval = onOverrideGlobalEval;
|
|
inherit priority template;
|
|
};
|
|
inherit content;
|
|
};
|
|
|
|
# Make the template traversal in function of the property traversal. If
|
|
# the template define a non-empty attribute set, then the property is
|
|
# copied only on all mentionned attributes inside the template.
|
|
# Otherwise, the property is kept on all sub-attribute definitions.
|
|
onOverrideDelay = name: p@{property, content, ...}:
|
|
let inherit (property) template; in
|
|
if isAttrs template && template != {} then
|
|
if hasAttr name template then
|
|
p // {
|
|
property = p.property // {
|
|
template = builtins.getAttr name template;
|
|
};
|
|
}
|
|
# Do not override the attribute \name\
|
|
else
|
|
content
|
|
# Override values defined inside the attribute \name\.
|
|
else
|
|
p;
|
|
|
|
# Ignore all values which have a higher value of the priority number.
|
|
onOverrideGlobalEval = valList:
|
|
let
|
|
defaultPrio = 100;
|
|
|
|
inherit (builtins) lessThan;
|
|
|
|
getPrioVal =
|
|
foldProperty
|
|
(foldFilter isOverride
|
|
(p@{property, content, ...}:
|
|
if lessThan content.priority property.priority then
|
|
content
|
|
else
|
|
content // {
|
|
inherit (property) priority;
|
|
}
|
|
)
|
|
(p@{property, content, ...}:
|
|
content // {
|
|
value = p // { content = content.value; };
|
|
}
|
|
)
|
|
) (value: { priority = defaultPrio; inherit value; });
|
|
|
|
prioValList = map getPrioVal valList;
|
|
|
|
higherPrio = fold (x: y:
|
|
if lessThan x.priority y then
|
|
x.priority
|
|
else
|
|
y
|
|
) defaultPrio prioValList;
|
|
in
|
|
map (x:
|
|
if x.priority == higherPrio then
|
|
x.value
|
|
else
|
|
mkNotdef
|
|
) prioValList;
|
|
|
|
}
|