John Ericson 44c8d83831 Create outputOf primop. ... In the Nix language, given a drv path, we should be able to construct another string referencing to one of its output. We can do this today with `(import drvPath).output`, but this only works for derivations we already have. With dynamic derivations, however, that doesn't work well because the `drvPath` isn't yet built: importing it like would need to trigger IFD, when the whole point of this feature is to do "dynamic build graph" without IFD! Instead, what we want to do is create a placeholder value with the right string context to refer to the output of the as-yet unbuilt derivation. A new primop in the language, analogous to `builtins.placeholder` can be used to create one. This will achieve all the right properties. The placeholder machinery also will match out the `outPath` attribute for CA derivations works. In 60b7121d2c we added that type of placeholder, and the derived path and string holder changes necessary to support it. Then in the previous commit we cleaned up the code (inspiration finally hit me!) to deduplicate the code and expose exactly what we need. Now, we can wire up the primop trivally! Part of RFC 92: dynamic derivations (tracking issue #6316) Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>		2023-08-14 09:37:37 -04:00
..
internal-api	Generate API docs with Doxygen	2023-03-10 12:51:06 -05:00
manual	Create outputOf primop.	2023-08-14 09:37:37 -04:00