From d0a836b0e1ee1034144d1e5b71df6ab285c8450e Mon Sep 17 00:00:00 2001 From: Griffin Smith Date: Sun, 23 Oct 2022 13:37:11 -0400 Subject: feat(tvix/eval): Implement comparison for lists Lists are compared lexicographically in C++ nix as of [0], and our updated nix test suites depend on this. This implements comparison of list values in `Value::nix_cmp` using a very similar algorithm to what C++ does - similarly to there, this requires passing in the VM so we can force thunks in the list elements as we go. [0]: https://github.com/NixOS/nix/commit/09471d2680292af48b2788108de56a8da755d661# Change-Id: I5d8bb07f90647a1fec83f775243e21af856afbb1 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7070 Autosubmit: grfn Reviewed-by: sterni Tested-by: BuildkiteCI --- tvix/eval/src/builtins/mod.rs | 2 +- .../src/tests/tvix_tests/eval-okay-compare-lists.exp | 1 + .../src/tests/tvix_tests/eval-okay-compare-lists.nix | 17 +++++++++++++++++ tvix/eval/src/value/list.rs | 10 ++++++++++ tvix/eval/src/value/mod.rs | 15 ++++++++++++++- tvix/eval/src/vm.rs | 2 +- tvix/verify-lang-tests/default.nix | 1 + 7 files changed, 45 insertions(+), 3 deletions(-) create mode 100644 tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.exp create mode 100644 tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.nix diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index ea431977bdb6..5c029605f1ec 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -418,7 +418,7 @@ fn pure_builtins() -> Vec { &[false, false], |args: Vec, vm: &mut VM| { Ok(Value::Bool(matches!( - args[0].force(vm)?.nix_cmp(&*args[1].force(vm)?)?, + args[0].force(vm)?.nix_cmp(&*args[1].force(vm)?, vm)?, Some(Ordering::Less) ))) }, diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.exp new file mode 100644 index 000000000000..3b7fd398198a --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.exp @@ -0,0 +1 @@ +[ false true true true false true false false false true false false false true true ] diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.nix new file mode 100644 index 000000000000..9b73df61d84e --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-compare-lists.nix @@ -0,0 +1,17 @@ +[ + ([1 2] < [1]) + ([1 2] < [2 3]) + ([1 2] < [2]) + ([1 2] < [1 2 3]) + ([3 4] < [1]) + ([1 2] > [1]) + ([1 2] > [2 3]) + ([1 2] > [2]) + ([1 2] > [1 2 3]) + ([3 4] > [1]) + ([1 2] <= [1]) + ([1 2] >= [2 3]) + ([1 2] >= [2]) + ([1 2] <= [1 2 3]) + ([3 4] >= [1]) +] diff --git a/tvix/eval/src/value/list.rs b/tvix/eval/src/value/list.rs index 8ea3db7aecf3..236a654ad88d 100644 --- a/tvix/eval/src/value/list.rs +++ b/tvix/eval/src/value/list.rs @@ -1,4 +1,6 @@ //! This module implements Nix lists. +use std::ops::Deref; + use crate::errors::ErrorKind; use crate::vm::VM; @@ -125,3 +127,11 @@ impl<'a> IntoIterator for &'a NixList { self.0.iter() } } + +impl Deref for NixList { + type Target = Vec; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} diff --git a/tvix/eval/src/value/mod.rs b/tvix/eval/src/value/mod.rs index 355540402d42..c590495b5344 100644 --- a/tvix/eval/src/value/mod.rs +++ b/tvix/eval/src/value/mod.rs @@ -351,12 +351,25 @@ impl Value { } /// Compare `self` against other using (fallible) Nix ordering semantics. - pub fn nix_cmp(&self, other: &Self) -> Result, ErrorKind> { + pub fn nix_cmp(&self, other: &Self, vm: &mut VM) -> Result, ErrorKind> { match (self, other) { // same types (Value::Integer(i1), Value::Integer(i2)) => Ok(i1.partial_cmp(i2)), (Value::Float(f1), Value::Float(f2)) => Ok(f1.partial_cmp(f2)), (Value::String(s1), Value::String(s2)) => Ok(s1.partial_cmp(s2)), + (Value::List(l1), Value::List(l2)) => { + for i in 0.. { + if i == l2.len() { + return Ok(Some(Ordering::Greater)); + } else if i == l1.len() { + return Ok(Some(Ordering::Less)); + } else if !l1[i].nix_eq(&l2[i], vm)? { + return l1[i].force(vm)?.nix_cmp(&*l2[i].force(vm)?, vm); + } + } + + unreachable!() + } // different types (Value::Integer(i1), Value::Float(f2)) => Ok((*i1 as f64).partial_cmp(f2)), diff --git a/tvix/eval/src/vm.rs b/tvix/eval/src/vm.rs index 6a5c56dc03bf..d011f651b982 100644 --- a/tvix/eval/src/vm.rs +++ b/tvix/eval/src/vm.rs @@ -123,7 +123,7 @@ macro_rules! cmp_op { ( $self:ident, $op:tt ) => {{ let b = $self.pop(); let a = $self.pop(); - let ordering = fallible!($self, a.nix_cmp(&b)); + let ordering = fallible!($self, a.nix_cmp(&b, $self)); let result = Value::Bool(cmp_op!(@order $op ordering)); $self.push(result); }}; diff --git a/tvix/verify-lang-tests/default.nix b/tvix/verify-lang-tests/default.nix index e05ef17a85bf..ca7ea4b348a2 100644 --- a/tvix/verify-lang-tests/default.nix +++ b/tvix/verify-lang-tests/default.nix @@ -53,6 +53,7 @@ let "eval-okay-zipAttrsWith.nix" = [ nix ]; # Comparable lists are not in Nix 2.3 "eval-okay-sort.nix" = [ nix ]; + "eval-okay-compare-lists.nix" = [ nix ]; # getAttrPos gains support for functionArgs-returned sets after 2.3 "eval-okay-getattrpos-functionargs.nix" = [ nix ]; }; -- cgit 1.4.1