Add option types.

svn path=/nixpkgs/trunk/; revision=15749
This commit is contained in:
Nicolas Pierron 2009-05-27 20:25:17 +00:00
parent 8c2a5ccdcb
commit 49b4942f0e

View File

@ -11,13 +11,227 @@ with import ./attrsets.nix;
rec {
mkOption = attrs: attrs // {_type = "option";};
hasType = x: isAttrs x && x ? _type;
typeOf = x: if hasType x then x._type else "";
isOption = attrs: (typeOf attrs) == "option";
mkOption = attrs: attrs // {
_type = "option";
# name (this is the name of the attributem it is automatically generated by the traversal)
# default (value used when no definition exists)
# example (documentation)
# description (documentation)
# type (option type, provide a default merge function and ensure type correctness)
# merge (function used to merge definitions into one definition: [ /type/ ] -> /type/)
# apply (convert the option value to ease the manipulation of the option result)
# options (set of sub-options declarations & definitions)
};
# Make the option declaration more user-friendly by adding default
# settings and some verifications based on the declaration content (like
# type correctness).
addOptionMakeUp = {name, recurseInto}: decl:
let
init = {
inherit name;
merge = mergeDefaultOption;
apply = lib.id;
};
mergeFromType = opt:
if decl ? type && decl.type ? merge then
opt // { merge = decl.type.merge; }
else
opt;
addDeclaration = opt: opt // decl;
ensureMergeInputType = opt:
if decl ? type then
opt // {
merge = list:
if all decl.type.check list then
opt.merge list
else
throw "One of the definitions has a bad type.";
}
else opt;
ensureDefaultType = opt:
if decl ? type && decl ? default then
opt // {
default =
if decl.type.check decl.default then
decl.default
else
throw "The default value has a bad type.";
}
else opt;
handleOptionSets = opt:
if decl ? type && decl.type.hasOptions then
opt // {
merge = list:
decl.type.iter
(path: opts: recurseInto path (decl.options ++ [opts]))
opt.name
(opt.merge list);
options = recurseInto (decl.type.docPath opt.name) decl.options;
}
else
opt;
in
foldl (opt: f: f opt) init [
# default settings
mergeFromType
# user settings
addDeclaration
# override settings
ensureMergeInputType
ensureDefaultType
handleOptionSets
];
# Merge a list of options containning different field. This is useful to
# separate the merge & apply fields from the interface.
mergeOptionDecls = opts:
if opts == [] then {}
else if tail opts == [] then
let opt = head opts; in
if opt ? options then
opt // { options = toList opt.options; }
else
opt
else
fold (opt1: opt2:
lib.addErrorContext "opt1 = ${lib.showVal opt1}\nopt2 = ${lib.showVal opt2}" (
# You cannot merge if two options have the same field.
assert opt1 ? default -> ! opt2 ? default;
assert opt1 ? example -> ! opt2 ? example;
assert opt1 ? description -> ! opt2 ? description;
assert opt1 ? merge -> ! opt2 ? merge;
assert opt1 ? apply -> ! opt2 ? apply;
assert opt1 ? type -> ! opt2 ? type;
if opt1 ? options || opt2 ? options then
opt1 // opt2 // {
options =
(toList (attrByPath ["options"] [] opt1))
++ (toList (attrByPath ["options"] [] opt2));
}
else
opt1 // opt2
)) {} opts;
# 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)
# path (path contatenated to the option name contained contained in the option set)
isOptionType = attrs: (typeOf attrs) == "option-type";
mkOptionType = attrs@{
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
}: { _type = "option-type";
inherit name check merge iter fold docPath hasOptions;
};
type = {
infere = mkOptionType {
name = "infered type";
};
enable = mkOptionType {
name = "boolean";
check = builtins.isBool;
merge = fold lib.or false;
};
int = mkOptionType {
name = "integer";
check = builtins.isInt;
};
string = mkOptionType {
name = "string";
check = x: builtins ? isString -> builtins.isString x;
merge = lib.concatStrings;
};
attrs = mkOptionType {
name = "attribute set";
check = builtins.isAttrs;
merge = fold lib.mergeAttrs {};
};
# derivation is a reserved keyword.
package = mkOptionType {
name = "derivation";
check = x: builtins.isAttrs x && x ? outPath;
};
list = elemType: mkOptionType {
name = "list of ${elemType.name}s";
check = value: 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 (path + ".*");
inherit (elemType) hasOptions;
};
attrsOf = elemType: mkOptionType {
name = "attribute set of ${elemType}s";
check = x: builtins.isAttrs x
&& fold (e: v: v && elemType.check e) true (lib.attrValues x);
merge = fold lib.mergeAttrs {};
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 (path + ".<name>");
inherit (elemType) hasOptions;
};
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.";
};
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;
};
optionSet = mkOptionType {
name = "option set";
check = x: builtins.isAttrs x;
hasOptions = true;
};
};
# !!! This function will be removed because this can be done with the
# multiple option declarations.
addDefaultOptionValues = defs: opts: opts //
builtins.listToAttrs (map (defName:
{ name = defName;
@ -82,6 +296,9 @@ rec {
if all isAttrs opts then
lib.zip (attr: opts:
let
recurseInto = name: attrs:
handleOptionSets optionHandler name attrs;
# Compute the path to reach the attribute.
name = if path == "" then attr else path + "." + attr;
@ -90,13 +307,12 @@ rec {
test = partition isOption opts;
decls = test.right; defs = test.wrong;
# Return the option declaration and add missing default
# attributes.
opt = {
inherit name;
merge = mergeDefaultOption;
apply = lib.id;
} // (head decls);
# Make the option declaration more user-friendly by adding default
# settings and some verifications based on the declaration content
# (like type correctness).
opt = addOptionMakeUp
{ inherit name recurseInto; }
(mergeOptionDecls decls);
# Return the list of option sets.
optAttrs = map delayProperties defs;
@ -105,10 +321,9 @@ rec {
# Remove undefined values that are coming from evalIf.
optValues = evalProperties defs;
in
if decls == [] then handleOptionSets optionHandler name optAttrs
if decls == [] then recurseInto name optAttrs
else lib.addErrorContext "while evaluating the option ${name}:" (
if tail decls != [] then throw "Multiple options."
else export opt optValues
export opt optValues
)
) opts
else lib.addErrorContext "while evaluating ${path}:" (notHandle opts);