Commit graph

24 commits

Author SHA1 Message Date
Vincent Ambo
a00e4730a5 feat(tvix/eval): implement assert operator
This implements `assert`, which evaluates an expression and aborts
evaluation if the value is not `true`.

At this point we should introduce eval-failed-* tests; probably
asserting against some representation of the error enum?

Change-Id: If54c8f616d89b829c1860a4835dde60a2cd70d7a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6230
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-01 17:41:22 +00:00
Vincent Ambo
59f50dc81a feat(tvix/eval): Implement OpResolveWith instruction
Change-Id: I4d2a69f28a6b6199b3ff48ef81135e7da9fe1c3b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6222
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-31 22:26:11 +00:00
Vincent Ambo
19878c5fef feat(tvix/eval): implement OpPopWith
Change-Id: I752d9428a73f893741746e9d5b79e8d8d570bb81
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6219
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-31 22:26:11 +00:00
Vincent Ambo
7cfdedfdfb feat(tvix/eval): compile with expression
Adds an additional structure to the compiler's scope to track the
runtime "with stack", i.e. the stack of values through which
identifiers should be dynamically resolved within a with-scope.

When encountering a `with` expression, the value from which the
bindings should be resolved is pushed onto the stack and tracked by
the compiler in the "with stack", as well as with a "phantom value"
which indicates that the stack contains an additional slot which is
not available to users via identifiers.

Runtime handling of this is not yet implemented.

Change-Id: I5e96fb55b6378e8e2a59c20c8518caa6df83da1c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6217
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-08-31 22:26:11 +00:00
Vincent Ambo
342b233a0a feat(tvix/eval): add local identifier access
This makes basic `let ... in ...` statements work correctly. It does
not yet account for the call frames pushed into the VM during function
application.

Change-Id: I67155171daf1a43011b96716dd9d1ab04b27db33
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6190
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-28 17:50:34 +00:00
Vincent Ambo
691a596aac feat(tvix/eval): compile simple let ... in ... expressions
These expressions now leave the binding values on the stack, and clean
up the scope after the body of the expression.

While variable access is not yet implemented (as the identifier node
remains unhandled), this already gives us the correct stack behaviour.

Change-Id: I138c20ace9c64502c94b2c0f99a6077cd912c00d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6188
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-28 17:50:34 +00:00
Vincent Ambo
d952b29fca chore(tvix/eval): add variant_size_differences warning for OpCode
This makes it possible to quickly detect code errors that might blow
up the size of the OpCode type.

Change-Id: I7662dd0aa30c4762c0f9e4fa346418c9ca8b9994
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6177
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-26 20:32:12 +00:00
Vincent Ambo
b8cec6d61e feat(tvix/vm): add opcodes for new Value::NotFound sentinel
This sentinel value is going to be used for certain nested accesses
into attribute sets.

There is a new instruction similar to `OpAttrsSelect` which leaves the
sentinel on the stack if a key is not found, instead of raising an
error.

Additionally, a new jump instruction makes its jump operation
conditional on finding such a sentinel value.

Change-Id: I2642f0a0bcc85bbe0ead68ea09a7dd794dbedeac
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6166
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-08-26 15:06:52 +00:00
Vincent Ambo
cf3e3b784b feat(tvix/eval): implement ? operator (single-level only)
This makes it possible to check things like `{} ? a` with a single
level of nesting.

Change-Id: I567c36fcfd2f9e2f60071acd3ebfe56dea59b26f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6161
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-08-26 09:02:38 +00:00
Vincent Ambo
20f5ccefeb feat(tvix/eval): implement attribute set access operator
Fairly straightforward, handling the optimised representations
manually and otherwise delegating to BTreeMap.

Note that parsing of raw identifiers is not yet implemented.

Encountering an identifier node usually means that there is locals
access going on, so we need a special case for compiling a node in
such a way that an identifier's literal value ends up on the stack.

Change-Id: I13fbab7ac657b17ef3f4c5859fe737c321890c8a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6158
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-26 09:02:38 +00:00
Vincent Ambo
671915837a fix(tvix/eval): add operation to assert boolean type
This operation is required because both sides of the logical operators
are strictly evaluated by Nix, even if the resulting value is not used
further.

For example, in our implementation of `&&`, if the left-hand side is
`true`, then the result of the expression is simply the right-hand
side value. This value must be asserted to be a boolean for the
semantics of the language to work correctly.

Change-Id: I34f5364f2a444753fa1d8b0a1a2b2d9cdf7c6700
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6157
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-26 09:02:38 +00:00
Vincent Ambo
c7c7ab9bd4 feat(tvix/compiler): implement || operator
Same dance as `&&` but logically inverted.

Change-Id: I213e200e3836527e9abe510f354ee7cd1f70d041
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6151
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-08-25 16:00:55 +00:00
Vincent Ambo
d9d94eb27f feat(tvix/eval): implement if/else expressions
These expressions use simple jumps to skip the correct expression
conditionally in the bytecode by advancing the instruction pointer.

Note that these expressions are already covered by a test behind the
`nix_tests` feature flag, but adding more is probably sensible.

Change-Id: Ibe0eba95d216321c883d3b6b5816e2ab6fe7eef1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6148
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-08-25 16:00:55 +00:00
Vincent Ambo
75a22321ce feat(tvix/eval): implement list concatenation
Change-Id: Icdf715d116371a9f139bdf95266410bf967bef25
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6144
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-08-25 12:07:30 +00:00
Vincent Ambo
4eafaae9e6 feat(tvix/eval): implement binary comparison operators
This is accomplished by simply delegating to the Rust implementations
of (Partial)Ord and (Partial)Eq, which are implemented for Value and
underlying wrapper types to behave like they do in Nix.

To ease the implementation overhead, a new comparison operator macro
has been added to the VM module.

Incomparable types will raise a new error variant when a comparison is
attempted, containing both supplied types. This mimics the information
carried in the error thrown by C++ Nix.

Change-Id: Ia19634d69119d40722f3ca672387bc3a80096998
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6143
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-08-25 12:07:30 +00:00
Vincent Ambo
058e77bab2 feat(tvix/eval): implement attrset update (//) operator
The underlying implementation does a few tricks based on which pair of
attrset representations is encountered.

Particularly the effect of short-circuiting the empty cases might be
relevant in nixpkgs/NixOS, due to the use of lib.optionalAttrs.

Change-Id: I22b978b1c69af12926489a71087c6a6219c012f3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6140
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-08-25 11:34:00 +00:00
Vincent Ambo
175eb97505 feat(tvix/eval): construct internal attribute path representation
This is required for constructing nested attribute sets at runtime.

There'll be quite a lot of optimisation potential with this solution
eventually, if it should turn out to be a bottleneck.

This introduces a conceptual change, in that the `Value` enum is now
an enum representing "all runtime values" instead of "all Nix language
types". This makes sense in general, as this type will also contain
Chunk representations etc. which are not exposed to users.

Change-Id: Ic5f72b2a0965b146c6a451efad34c6a81ca1aad8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6103
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
2022-08-13 20:24:12 +00:00
Vincent Ambo
a93933b487 feat(tvix): implement string interpolation
This adds a new instruction which assembles an interpolated string
from a specified number of fragments, which are already going to be
located on the stack in the right position.

This will raise a type error if any of the fragments do not evaluate
to a string.

Change-Id: I5756248fa3e9fcc3d063c14db40b332f7e20a588
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6098
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-13 18:28:36 +00:00
Vincent Ambo
5763b62172 feat(tvix/vm): implement list construction
Change-Id: Iec2b4910800ab29daae6d71b58a8acd14ccb1cc1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6094
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
2022-08-13 15:35:24 +00:00
Vincent Ambo
57a723aaa9 feat(tvix/eval): implement trivial attribute set literals
Implements attribute set literals without nesting. Technically this
already supports dynamic key fragments (evaluating to strings), though
the only way to create these (interpolation) is not yet implemented.

However, creating simple attribute sets like `{ }`, or `{ a = 15; }`
or `{ a = 10 * 2; }` works.

Recursive attribute sets are not yet implemented as we do not have any
kind of scope access yet anyways.

This is implemented using a new instruction that creates an attribute
set with a given number of elements by popping key/value pairs off the
stack.

Change-Id: I0f9aac7a131a112d3f66b131297686b38aaeddf2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6091
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-13 15:31:50 +00:00
Vincent Ambo
ded0fb9e21 feat(tvix/eval): implement equality operator
Change-Id: I9dd54aed72cd7e67593dc76f5a046ebbda40c26f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6078
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-12 14:09:27 +00:00
Vincent Ambo
72be759e1e feat(tvix/eval): implement unary negation operator
Change-Id: I5d012cc073e55d79d7b34b88283aab3164864293
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6075
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-12 13:24:10 +00:00
Vincent Ambo
d35ecc0caf feat(tvix/eval): implement simple arithmetic binary operations
Implements simple arithmetic operations (+, -, *, /).

There is some scaffolding included to pop and coerce pairs of numbers,
as the Nix language will let arithmetic operators apply to arbitrary
pairs of number types (always resulting in floats if the types are
mixed).

Change-Id: I5f62c363bdea8baa6ef812cc64c5406759d257cf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6074
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-12 13:24:10 +00:00
Vincent Ambo
48a7449834 feat(tvix/eval): add initial opcode representation
Change-Id: Ibc7685a6b0b92e08f0b6c82cf7d9b04fbb593a4e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6068
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
2022-08-12 13:05:16 +00:00