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nixpkgs/pkgs/lib/modules.nix
Nicolas Pierron 37ce2ca949 Handles cases where developers ""cannot"" put their initial modules in
other files.

Imports of imported attribute set are not working anymore because this
feature is hard to maintain and because this a potential source of error.

Imports are only accepted inside named modules where the system has some
control over mutual inclusion.

svn path=/nixpkgs/trunk/; revision=17144
2009-09-15 00:21:39 +00:00

92 lines
2.2 KiB
Nix

# NixOS module handling.
let lib = import ./default.nix; in
with { inherit (builtins) head tail; };
with import ./trivial.nix;
with import ./lists.nix;
with import ./misc.nix;
with import ./attrsets.nix;
with import ./properties.nix;
rec {
# Unfortunately this can also be a string.
isPath = x: !(
builtins.isFunction x
|| builtins.isAttrs x
|| builtins.isInt x
|| builtins.isBool x
|| builtins.isList x
);
importIfPath = path:
if isPath path then
import path
else
path;
applyIfFunction = f: arg:
if builtins.isFunction f then
f arg
else
f;
# Convert module to a set which has imports / options and config
# attributes.
unifyModuleSyntax = m:
let
getImports = m:
if m ? config || m ? options then
attrByPath ["imports"] [] m
else
toList (rmProperties (attrByPath ["require"] [] (delayProperties m)));
getImportedPaths = m: filter isPath (getImports m);
getImportedSets = m: filter (x: !isPath x) (getImports m);
getConfig = m:
removeAttrs (delayProperties m) ["require"];
in
if m ? config || m ? options then
m
else
{
imports = getImportedPaths m;
config = getConfig m;
} // (
if getImportedSets m != [] then
assert tail (getImportedSets m) == [];
{ options = head (getImportedSets m); }
else
{}
);
moduleClosure = initModules: args:
let
moduleImport = m:
(unifyModuleSyntax (applyIfFunction (importIfPath m) args)) // {
# used by generic closure to avoid duplicated imports.
key = if isPath m then m else
/bad/developer/implies/bad/error/messages;
};
getImports = m: attrByPath ["imports"] [] m;
in
(lazyGenericClosure {
startSet = map moduleImport (filter isPath initModules);
operator = m: map moduleImport (getImports m);
}) ++ (map moduleImport (filter (m: ! isPath m) initModules));
selectDeclsAndDefs = modules:
lib.concatMap (m:
if m ? config || m ? options then
[ (attrByPath ["options"] {} m) ]
++ [ (attrByPath ["config"] {} m) ]
else
[ m ]
) modules;
}