# Definitions related to run-time type checking. Used in particular # to type-check NixOS configurations. let lib = import ./default.nix; in with import ./lists.nix; with import ./attrsets.nix; with import ./options.nix; rec { hasType = x: isAttrs x && x ? _type; typeOf = x: if hasType x then x._type else ""; setType = typeName: value: value // { _type = typeName; }; # name (name of the type) # check (boolean function) # merge (default merge function) # iter (iterate on all elements contained in this type) # fold (fold all elements contained in this type) # hasOptions (boolean: whatever this option contains an option set) # delayOnGlobalEval (boolean: should properties go through the evaluation of this option) # docPath (path concatenated to the option name contained in the option set) isOptionType = attrs: typeOf attrs == "option-type"; mkOptionType = { name , check ? (x: true) , merge ? mergeDefaultOption # Handle complex structure types. , iter ? (f: path: v: f path v) , fold ? (op: nul: v: op v nul) , docPath ? lib.id # If the type can contains option sets. , hasOptions ? false , delayOnGlobalEval ? false }: { _type = "option-type"; inherit name check merge iter fold docPath hasOptions delayOnGlobalEval; }; types = rec { inferred = mkOptionType { name = "inferred type"; }; bool = mkOptionType { name = "boolean"; check = lib.traceValIfNot builtins.isBool; merge = fold lib.or false; }; int = mkOptionType { name = "integer"; check = lib.traceValIfNot builtins.isInt; }; string = mkOptionType { name = "string"; check = lib.traceValIfNot (x: builtins ? isString -> builtins.isString x); merge = lib.concatStrings; }; envVar = mkOptionType { name = "environment variable"; inherit (string) check; merge = lib.concatStringsSep ":"; }; attrs = mkOptionType { name = "attribute set"; check = lib.traceValIfNot builtins.isAttrs; merge = fold lib.mergeAttrs {}; }; # derivation is a reserved keyword. package = mkOptionType { name = "derivation"; check = lib.traceValIfNot isDerivation; }; listOf = types.list; list = elemType: mkOptionType { name = "list of ${elemType.name}s"; check = value: lib.traceValIfNot isList value && all elemType.check value; merge = concatLists; iter = f: path: list: map (elemType.iter f (path + ".*")) list; fold = op: nul: list: lib.fold (e: l: elemType.fold op l e) nul list; docPath = path: elemType.docPath (path + ".*"); inherit (elemType) hasOptions; # You cannot define multiple configurations of one entity, therefore # no reason justify to delay properties inside list elements. delayOnGlobalEval = false; }; attrsOf = elemType: mkOptionType { name = "attribute set of ${elemType.name}s"; check = x: lib.traceValIfNot builtins.isAttrs x && fold (e: v: v && elemType.check e) true (lib.attrValues x); merge = lib.zip (name: elemType.merge); iter = f: path: set: lib.mapAttrs (name: elemType.iter f (path + "." + name)) set; fold = op: nul: set: fold (e: l: elemType.fold op l e) nul (lib.attrValues set); docPath = path: elemType.docPath (path + "."); inherit (elemType) hasOptions delayOnGlobalEval; }; uniq = elemType: mkOptionType { inherit (elemType) name check iter fold docPath hasOptions; merge = list: if tail list == [] then head list else throw "Multiple definitions. Only one is allowed for this option."; }; none = elemType: mkOptionType { inherit (elemType) name check iter fold docPath hasOptions; merge = list: throw "No definitions are allowed for this option."; }; nullOr = elemType: mkOptionType { inherit (elemType) name merge docPath hasOptions; check = x: builtins.isNull x || elemType.check x; iter = f: path: v: if v == null then v else elemType.iter f path v; fold = op: nul: v: if v == null then nul else elemType.fold op nul v; }; # !!! this should be a type constructor that takes the options as # an argument. optionSet = mkOptionType { name = "option set"; # merge is done in "options.nix > addOptionMakeUp > handleOptionSets" merge = lib.id; check = x: isAttrs x || builtins.isFunction x; hasOptions = true; delayOnGlobalEval = true; }; }; }