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* Simplify the implementation of "derivation" a bit: lift out the

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common attribution so that they're evaluated only once, etc.  Note
  that the default output is now the first element of the "outputs"
  attribute, rather than the first element of the sorted list of
  outputs.  This seems more user-friendly.
This commit is contained in:
Eelco Dolstra 2012-01-04 11:04:19 +00:00
parent 71f3c46cf6
commit 83647f4ef1
1 changed files with 11 additions and 18 deletions
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29
corepkgs/derivation.nix
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@ -1,31 +1,24 @@
attrs:
/* This is the implementation of the ‘derivation’ builtin function.
It's actually a wrapper around the ‘derivationStrict’ primop. */
drvAttrs @ { outputs ? [ "out" ], ... }:
let
strict = derivationStrict attrs;
strict = derivationStrict drvAttrs;
attrValues = attrs:
map (name: builtins.getAttr name attrs) (builtins.attrNames attrs);
commonAttrs = drvAttrs // (builtins.listToAttrs outputsList) // { all = map (x: x.value) outputsList; };
outputToAttrListElement = outputName:
{ name = outputName;
value = attrs // {
value = commonAttrs // {
outPath = builtins.getAttr outputName strict;
drvPath = strict.drvPath;
type = "derivation";
currentOutput = outputName;
} // outputsAttrs // { all = allList; };
};
};
outputsList =
if attrs ? outputs
then map outputToAttrListElement attrs.outputs
else [ (outputToAttrListElement "out") ];
outputsList = map outputToAttrListElement outputs;
outputsAttrs = builtins.listToAttrs outputsList;
allList = attrValues outputsAttrs;
head = if attrs ? outputs then builtins.head attrs.outputs else "out";
in builtins.getAttr head outputsAttrs
in (builtins.head outputsList).value