nixpkgs/lib/types.nix
Eelco Dolstra 0afdb1e933 Add option type "str" for unique strings
An annoying and dangerous property of "types.string" is that it merges
multiple definitions by concatenating them, which almost never
produces a sensible result.  (Those options for which it does make
sense typically should use "types.lines" instead, and things only work
because the option definitions already end in a newline.)  Of course,
you can use "types.uniq types.string", but that's rather verbose, and
inconsistent with other basic types like "types.int".

Changing the behaviour of "types.string" to be unique by default is
not an option, given the large number of options that use it.  So
instead, we now have "types.str", which is equivalent to "types.uniq
types.string".
2013-10-29 13:45:30 +01:00

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# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
let lib = import ./default.nix; in
with lib.lists;
with lib.attrsets;
with lib.options;
with lib.trivial;
with lib.modules;
rec {
isType = type: x: (x._type or "") == type;
typeOf = x: x._type or "";
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.
merge ? mergeDefaultOption
, # Return a flat list of sub-options. Used to generate
# documentation.
getSubOptions ? prefix: {}
}:
{ _type = "option-type";
inherit name check merge getSubOptions;
};
types = rec {
unspecified = mkOptionType {
name = "unspecified";
};
bool = mkOptionType {
name = "boolean";
check = builtins.isBool;
merge = args: fold lib.or false;
};
int = mkOptionType {
name = "integer";
check = builtins.isInt;
};
str = mkOptionType {
name = "string";
check = builtins.isString;
merge = mergeOneOption;
};
# Deprecated; should not be used because it quietly concatenates
# strings, which is usually not what you want.
string = mkOptionType {
name = "string";
check = builtins.isString;
merge = args: lib.concatStrings;
};
# Like string, but add newlines between every value. Useful for
# configuration file contents.
lines = mkOptionType {
name = "string";
check = builtins.isString;
merge = args: lib.concatStringsSep "\n";
};
commas = mkOptionType {
name = "string";
check = builtins.isString;
merge = args: lib.concatStringsSep ",";
};
envVar = mkOptionType {
name = "environment variable";
inherit (string) check;
merge = args: lib.concatStringsSep ":";
};
attrs = mkOptionType {
name = "attribute set";
check = isAttrs;
merge = args: fold lib.mergeAttrs {};
};
# derivation is a reserved keyword.
package = mkOptionType {
name = "derivation";
check = isDerivation;
merge = mergeOneOption;
};
path = mkOptionType {
name = "path";
# Hacky: there is no isPath primop.
check = x: builtins.unsafeDiscardStringContext (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 = value: isList value && all elemType.check value;
merge = args: defs: imap (n: def: elemType.merge (addToPrefix args (toString n)) [def]) (concatLists defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
};
attrsOf = elemType: mkOptionType {
name = "attribute set of ${elemType.name}s";
check = x: isAttrs x && all elemType.check (lib.attrValues x);
merge = args: lib.zipAttrsWith (name:
elemType.merge (addToPrefix (args // { inherit name; }) name));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
};
# List or attribute set of ...
loaOf = elemType:
let
convertIfList = defIdx: def:
if isList def then
listToAttrs (
flip imap def (elemIdx: elem:
{ name = "unnamed-${toString defIdx}.${toString elemIdx}"; value = elem; }))
else
def;
listOnly = listOf elemType;
attrOnly = attrsOf elemType;
in mkOptionType {
name = "list or attribute set of ${elemType.name}s";
check = x:
if isList x then listOnly.check x
else if isAttrs x then attrOnly.check x
else false;
merge = args: defs: attrOnly.merge args (imap convertIfList defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
};
uniq = elemType: mkOptionType {
inherit (elemType) name check;
merge = mergeOneOption;
getSubOptions = elemType.getSubOptions;
};
none = elemType: mkOptionType {
inherit (elemType) name check;
merge = args: list:
throw "No definitions are allowed for the option `${showOption args.prefix}'.";
getSubOptions = elemType.getSubOptions;
};
nullOr = elemType: mkOptionType {
name = "null or ${elemType.name}";
check = x: builtins.isNull x || elemType.check x;
merge = args: defs:
if all isNull defs then null
else if any isNull defs then
throw "The option `${showOption args.prefix}' is defined both null and not null, in ${showFiles args.files}."
else elemType.merge args defs;
getSubOptions = elemType.getSubOptions;
};
functionTo = elemType: mkOptionType {
name = "function that evaluates to a(n) ${elemType.name}";
check = builtins.isFunction;
merge = args: fns:
fnArgs: elemType.merge args (map (fn: fn fnArgs) fns);
getSubOptions = elemType.getSubOptions;
};
submodule = opts:
let opts' = toList opts; in
mkOptionType rec {
name = "submodule";
check = x: isAttrs x || builtins.isFunction x;
merge = args: defs:
let
coerce = def: if builtins.isFunction def then def else { config = def; };
modules = opts' ++ map coerce defs;
in (evalModules { inherit modules args; prefix = args.prefix; }).config;
getSubOptions = prefix: (evalModules
{ modules = opts'; inherit prefix;
# FIXME: hack to get shit to evaluate.
args = { name = ""; }; }).options;
};
# 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";
};
};
/* Helper function. */
addToPrefix = args: name: args // { prefix = args.prefix ++ [name]; };
}