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/value/list.rs | 10 ++++++++++ tvix/eval/src/value/mod.rs | 15 ++++++++++++++- 2 files changed, 24 insertions(+), 1 deletion(-) (limited to 'tvix/eval/src/value') diff --git a/tvix/eval/src/value/list.rs b/tvix/eval/src/value/list.rs index 8ea3db7aec..236a654ad8 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 355540402d..c590495b53 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)), -- cgit 1.4.1