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>
