I've had the notion that builtins.genericClosure can be used to express
any recursive algorithm, but a proof is much better than a notion of
course! In this case we can easily show this by implementing a function
that converts a tail recursive function into an application of
builtins.genericClosure.
This is possible if the function resolves its self reference using a
fixed point which allows us to pass a function that encodes the call to
self in a returned attribute set, leaving the actual call to
genericClosure's operator. Additionally, some tools for collecting meta
data about functions (argCount) and calling arbitrary functions (apply,
unapply) are necessary.
Change-Id: I7d455db66d0a55e8639856ccc207639d371a5eb8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5292
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: sterni <sternenseemann@systemli.org>
As a complementation to builtins.functionArgs this function checks if
the function has a set pattern that contains an ellipsis
(i. e. `{ [arg, [ arg1, [ … ]]] ... }:`). The implementation of this is
pretty cursed however since there is no clean way to do this in vanilla
nix: We need to match on the output of builtins.toXML which does try to
serialize functions by outputting their argument and information about
it (whether it is a normal argument or a attribute set pattern, in the
latter case it also serialize every component of the pattern).
Change-Id: I0f33721811a3180cec205a0c98e6d92e10e92075
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2950
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
What you see here is mostly the fallout of me implementing a correct
urlencode implementation in nix for Profpatsch's blog implementation
(although they'll probably keep it at arm's length).
Where I want to go from here:
* Extend this library towards general purpose nix™, mainly by
implementing missing interfaces which you'd still have to use
<nixpkgs/lib> for right now. Reexposing parts of <nixpkgs/lib>
with better naming is fine for now, at some point I'd contemplate
making this depend on nothing outside of depot, maybe even itself
(should be easy we only use yants for an easily replaceable check).
* Improve error messages possibly by carefully reintroducing yants. I
originally typed essentially everything using yants, but turns out
this can a) be dangerous when stuff you are handling throws because
type checking means evaluating and b) has a incredible performance
cost in some cases.
* Reexpose builtins with better naming and slightly wrapped so they
don't unrecoverably throw in cases where a null or something would
suffice.
Change-Id: I33ab08ca4e62dbc16b86c66c653935686e6b0e79
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2541
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
