maurice/snix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add a mechanism for derivation attributes to reference the derivation's outputs

Browse source 
For example, you can now say:

  configureFlags = "--prefix=${placeholder "out"} --includedir=${placeholder "dev"}";

The strings returned by the ‘placeholder’ builtin are replaced at
build time by the actual store paths corresponding to the specified
outputs.

Previously, you had to work around the inability to self-reference by doing stuff like:

  preConfigure = ''
    configureFlags+=" --prefix $out --includedir=$dev"
  '';

or rely on ad-hoc variable interpolation semantics in Autoconf or Make
(e.g. --prefix=\$(out)), which doesn't always work.
This commit is contained in:
Eelco Dolstra 2016-08-17 15:12:54 +02:00
parent ac841a4679
commit 22d6e31fc6
7 changed files with 63 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

14
src/libexpr/primops.cc
View file

@ -673,6 +673,19 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
}
/* Return a placeholder string for the specified output that will be
substituted by the corresponding output path at build time. For
example, ‘placeholder "out"’ returns the string
/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9. At build
time, any occurence of this string in an derivation attribute will
be replaced with the concrete path in the Nix store of the output
‘out’. */
static void prim_placeholder(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
mkString(v, hashPlaceholder(state.forceStringNoCtx(*args[0], pos)));
}
/*************************************************************
* Paths
*************************************************************/
@ -1893,6 +1906,7 @@ void EvalState::createBaseEnv()
// Derivations
addPrimOp("derivationStrict", 1, prim_derivationStrict);
addPrimOp("placeholder", 1, prim_placeholder);
// Networking
addPrimOp("__fetchurl", 1, prim_fetchurl);