These do essentially the same, but return different error variants as
upstream Nix considers `throw` to be (sometimes) catchable.
Change-Id: I1a9ea84567d46fb37287dbf3f3f67052f9382cca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6259
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
The set of things that can leak out of `builtins` into the global
scope is statically known (it is what Nix 2.3 leaks there,
essentially).
This is a mild change over the previous mechanism, where instead at
the point where the `builtins` set is constructed we "lift" the
globals out of there (if they exist).
This way users will still eventually be able to add additional
builtins, HOWEVER they will not be able to leak them into the global
scope.
Note that upstream Nix technically leaks _all_ builtins into the
global scope using the `__*` prefix, but we are trying to avoid this
in Tvix if it is not required in nixpkgs.
Change-Id: Ie9dec2ce33740134f3b2464eba3749f421dd5953
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6258
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Adds a new builtins module in which builtins can be constructed. The
functions in this module should return a correctly structured value to
be passed to the compiler's `globals`.
This is wired up all the way to the compiler with an example
`toString` builtin, available as a global. Note that this does not yet
actually behave like the real toString, which has some differences
from `Display`.
Change-Id: Ibb5f6fbe6207782fdf2434435567fc1bd80039a5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6254
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
