This will respect `recurseForDerivations` when iterating over attrsets.
Example expression:
``` nix
{ system ? builtins.currentSystem }:
{
recurseForDerivations = true;
# This should build as it's in the top-level attrset
drvA = derivation {
inherit system;
name = "drvA";
builder = ":";
};
dontRecurse = {
# This shouldn't build as `recurseForDerivations = true;` is not set
# recurseForDerivations = true;
# This should not build
drvB = derivation {
inherit system;
name = "drvA";
builder = ":";
};
};
recurse = {
# This should build
recurseForDerivations = true;
# This should not build
drvC = derivation {
inherit system;
name = "drvC";
builder = ":";
};
};
}
```
The output of the evaluator should only include either the full
derivation (not yet implemented) or fields not directly accessible
from the drv such as meta.
Right now the output is a fairly arbitrary selection of fields.