Adding `import` to builtins causes causes a bootstrap cycle because
the `import` builtin needs to be initialised with the set of globals
before being inserted into the globals, which also must contain
itself.
To break out of the cycle this hack wraps the builtins passed to the
compiler in an `Rc` (probably sensible anyways, as they will end up
getting cloned a bunch), containing a RefCell which gives us mutable
access to the builtins.
This opens up a potentially dangerous footgun in which we could mutate
the builtins at runtime leading to different compiler invocations
seeing different builtins, so it'd be nice to have some kind of
"finalised" status for them or some such, but I'm not sure how to
represent that atm.
Change-Id: I25f8d4d2a7e8472d401c8ba2f4bbf9d86ab2abcb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6867
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
This adds an initial working version of builtins.import which
encapsulates the entire functionality of `import` within the builtin
itself, without requiring any changes in the compiler or VM.
The key insight that enables this is that we can simply return a Thunk
from `import` that is constructed from the output of running the
compiler and - ta-da! - no other component needs to know about it.
A couple of notes:
* builtins.import needs to capture variables like the SourceCode
structure. This means it can not currently be constructed the same
way as other builtins and has special handling, which leaks out to
`eval.rs`. I have postponed dealing with that until we have this
working a bit more.
* the `globals` are not yet passed through
* the error representation for the new variants is absolutely not done
yet, we probably want to switch to something that supports
cause-chaining now (like miette)
* there is no mechanism for emitting warnings at runtime; we need to
add that
Change-Id: I3117a7ae3ff2432bf44f5ff05ad35f47faca31d5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6857
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
For some upcoming builtins (notably, import) we need to capture
arguments in the builtin's implementation.
To allow this, we can no longer use function pointers for builtins,
but must use a reference-counted closure object instead.
Unfortunately this adds an extra pointer operation to every builtin
call. We should benchmark this later against having a split builtin
representation.
Change-Id: I109d98d0e25998870542f47573eb1ec2e546f2a2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6856
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
nixpkgs has hardcoded references to Nix versions, we need to provide
it with something that looks like a Nix version while actually being a
Tvix version.
For now, we do this by stealing a trick out of the browser book and
constructing a version that looks like a Nix version to Nix, but like
a Tvix version to people who know what they are looking for.
Nevermind that we don't actually have any kind of versioning for
Tvix (yet?), other than depot revisions.
Change-Id: I7ce8079dd8164a2079891d38e707f09a45f0bbc1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6858
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Returns time since epoch in seconds.
This has a slight behaviour difference from Nix, in that we don't pin
the time between REPL entries (Nix pins it for the program lifetime),
but this is probably inconsequential as long as it is pinned during an
evaluation.
Change-Id: I010c02e93097a209d8ad69e278397c7e30e54c86
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6846
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Allows impure builtins that have a different shape than a Rust
function pointer; specifically this is required for
builtins.currentTime which does not work in WASM.
Change-Id: I1362d8eeafe770ce4d1c5ebe4d119aeb0abb5c9b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6849
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Concatenates (but not flattens) a list of lists.
Change-Id: I692e0b3e7b5a5ff93d5768d3a27849b432ec5747
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6843
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This was added in preparation for some builtins that don't exist yet
and is producing some noise during compilation.
Change-Id: I51fb0d14c3edf0bd6d9a288d50e44dacf35166c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6769
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This is a little ugly because the plain Iterator::filter method can
not be used (it does not support fallible primitives), so we need to
resort to an `Iterator::filter_map` and deal with the wrapping in
Options everywhere.
This prevents use of `?` which introduces the need for some matching,
but it's not *too* bad.
Change-Id: Ie2c3c0c9756c4c627176f64fb4e0054e717c26d1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6765
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Fairly straightforward, only thing of note is that we coerce (weakly) to
string here as well.
Change-Id: I03b427e657e402f1f9eb0f795b689bbf5092aba1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6745
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
The simplest solution seems to be to pass references to arithmetic_op!()
which avoids the moving annoyance we had to deal with in the
builtins (no more popping!). We then use .force() to force the values
and dereference any Thunks (which arithmetic_op! doesn't do for us).
Change-Id: I0eb8ad60e80a0b3ba9d9f411e973ef8bcf136989
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6724
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Sketch out a new set of "impure" builtins, which supplement the existing
set of "pure" builtins but are gated behind a feature flag, which allows
them to be omitted by crates depending on tvix-eval that only want pure
evaluation, such as tvixbolt.
Change-Id: I2736017b5c9b4776bbba8758e108ec84887abd66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6655
Reviewed-by: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
This was derived from
else if (c1 == "" && n2) return true; // true implies c1 < n2
However, this has no effect since Word always looses out against Number
anyways and the `pre` rules are also unaffected by this change – since
this only affects comparison of an empty Word part with a Number.
Change-Id: Ia04e42ac726352b688c87674b0fdb355f06edbcb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6722
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This is necessary because builtins.compareVersions compares versions in
a subtly not-quite-but-still-lexicographical way: `pre` for example can
have an effect if it is post-fixed: `2.3 < 2.3pre`. This is a violation
of the rule that in a lexicographical ordering, the longer string is
considered greater if they are otherwise equal. builtins.compareVersion
is comparing lexicographically though, if you do the following
transformation beforehand:
2.3 --split--> [ "2" "3" ] --append--> [ "2" "3" "" ]
2.3pre --split--> [ "2" "3" "pre" ] --append--> [ "2" "3" "pre" "" ]
Comparing the transformed version is then done lexicographically:
2.3 < 2.3.0pre since [ "2" "3" "" ] < [ "2" "3" "0" "pre" ]
Here, the `pre` rule never comes into effect because no comparison on it
happens, instead we use the longer string rule of a lexicographical
comparison.
In the C++ codebase, the reason for this behavior is that the
iterator-esque construct they use always yields the empty string before
it exposes it has been fully consumed. This is probably intentional to
support the postfixed `pre` which is, for example, used by NixOS
versions (e.g. unstable post 22.05 is 22.11-pre). We replicate this
behavior using the `Chain` iterator in `VersionPartsIter::new_for_cmp`.
Change-Id: I021c69aa27b0b7deb949dffe50ed18b6de3a7b1f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6720
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This is based on the [relevant code] in C++ Nix. Our version has more
branches because the C++ one only checks if it is less than or not, so
can save handling a few cases. We on the other hand, can avoid calling
the algorithm twice. It'd be nice to implement proptests for this in the
future and to make sure that this weird little algorithm doesn't violate
the Ord laws.
[relevant code]: cd35bbbeef/src/libstore/names.cc (L81-L94)
Change-Id: I46642e6da5eac7c0883cdce860622cdba04cd12b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6719
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This was fairly easy, thanks to the work already done by Thomas Frank.
However, the implementation is suboptimal because we parse number parts
only to convert them back to strings afterwards. I've chosen to tackle
this problem in the future, since having an (inefficient) implementation
of splitVersion will be helpful for debugging the slight discrepancies
between C++ Nix and Tvix in the case of compareVersions.
Change-Id: Id6ed8eeb77663ff650c8c53ea952875b1fb7ea84
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6688
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This makes it possible to call a callable value (builtin or
closure/lambda) directly, without unwrapping it first. This is needed
for pretty much all higher-order functions to work correctly.
This is mostly equivalent to the previous code in coerce_to_string for
calling `__toString`, except it expects the argument(s) to already be
placed on the stack.
Note that the span for the `NotCallable` error is not currently
guaranteed to make any sense, will experiment with this.
Change-Id: I821224368d438a28900858b343defc1817e46a0a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6717
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
As we already have a VM passed to the builtins, we can simply execute
the provided closure/lambda in it for each value.
The primary annoyance with this is that we have to clone the upvalues
for each element, but we can try making this cheaper in the
future (it's also a general problem in the VM itself).
Change-Id: I5bcf56d58c509c0eb081e7cf52f6093216451ce4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6714
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Previously we only matched the outer constructor after forcing which
would mean that we would always return `false` if the inspected value
was a thunk, regardless what value would be present inside.
Change-Id: I361ea6e855e23ef8e5b59098a50b9cd59253803f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6692
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Previously, this would almost always crash because list items are
thunked more often nowadays and selecting from a thunk would fail. Also
we no longer pop from args, accessing it by index should avoid an
unnecessary clone here.
Change-Id: I4410c4c2e28cc255a2c7cf2a5322db3d2c556a0e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6693
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Instead of arity, we pass a array reference to Builtin::new that
describes how many arguments there are and which of them need to be
forced, eliminating the need to force manually.
Note that this change doesn't fix some of the instances where the the
Builtin doesn't consider that the value could be a Thunk.
Change-Id: Iadb58bb79886c30dc6b09dcf0ffad8abf28036a1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6662
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
TL;DR:
- support `builtins.tail`
- define `ErrorKind::TailEmptyList` and canonical error code
- support basic unit tests
Unsure whether or not the error should be a dedicated `ErrorKind`...
Change-Id: Iae90fda1bb21ce7bdb1aaa2aeb2b8c1e6dcb0f05
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6545
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Refactor the `force!` macro to a method on `Value` which returns a
smart-pointer-esque type, which simplifies the callsite and eliminates
rightward drift, especially for high-arity builtins.
Change-Id: I97a7837580accfb4bbd03b24f2acdbd38645efa5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6656
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This function is necessary for all builtins that expect some form of
path as an argument. It is merely a wrapper around coerce_to_string that
can shortcut if we already have a path. The absolute path check is done
in the same way as in C++ Nix for compatibility, although it should
probably be revised in the long term (think about Windows, for example).
Since coercing to a path is not an operation possible in the language
directly, this function can live in the builtins module as the only
place it is required.
Change-Id: I69ed5455c00d193fea88b8fa83e28907a761cab5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6574
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Define `.len()` method on `NixAttrs` to preallocate the capacity of the result
vector.
Also anchor an errant comment to its context (I think).
Change-Id: I268f15025d453d7b3ae1146558c80e51433dd2a8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6546
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
Implement C++ Nix's `EvalState::coerceToString` minus some of the Path
/ store handling. This is currently only used for `toString` which does
all possible coercions, but we've already prepared the weaker coercion
variant which is e.g. used for builtins that expect string arguments.
`EvalState::coerceToPath` is still missing for builtins that need a
path, but it'll be easy to build on top of this.
Change-Id: I78d15576b18921791d04b6b1e964b951fdef22c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6571
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This prevents Nix programs to observe the "internal" type of thunks.
Possibly .type_of() is also an area of the runtime where we should panic
if "internal" would ever be returned.
Change-Id: I9f358044c48ad64896fb6a1b1a42f00a29efac00
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6539
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
As pointed out by grfn on cl/6091
Change-Id: I28308577b7cf99dffb4a4fd3cc8783eb9ab4d0d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6460
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This introduces a macro to do the forcing, but this solution isn't
very nice and also does not work in all cases yet.
Change-Id: Icd18862ec47edb82c0efc3af5835a6cb6126f629
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6456
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
