nixpkgs/pkgs/lib/types.nix
Nicolas Pierron 56ed820f84 Add systems.nix give more control over the increasing list of supported
systems.  This is not yet used because it has to be integrated with the
current system.

svn path=/nixpkgs/branches/stdenv-updates/; revision=18468
2009-11-19 17:19:39 +00:00

150 lines
4.5 KiB
Nix

# 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}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 + ".<name>");
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;
};
};
}