diff options
author | William Carroll <wpcarro@gmail.com> | 2022-09-05T18·41-0700 |
---|---|---|
committer | clbot <clbot@tvl.fyi> | 2022-09-15T16·48+0000 |
commit | 85b3f17007825b023d549d8e926322797e08ce6d (patch) | |
tree | a979ba95000ac2495868a89d78baa4c1d81bb33e | |
parent | 05958703410d37f874c4705cabbbba2082c555f7 (diff) |
feat(tvix/eval): Support builtins.head r/4862
TL;DR: - support `builtins.head` - define `ErrorKind::IndexOutOfBounds` and canonical error code - support basic unit tests Change-Id: I859107ffb4e220cba1be8c2ac41d1913dcca37ff Reviewed-on: https://cl.tvl.fyi/c/depot/+/6544 Reviewed-by: wpcarro <wpcarro@gmail.com> Autosubmit: wpcarro <wpcarro@gmail.com> Reviewed-by: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
-rw-r--r-- | tvix/eval/src/builtins/mod.rs | 8 | ||||
-rw-r--r-- | tvix/eval/src/errors.rs | 10 | ||||
-rw-r--r-- | tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.exp | 1 | ||||
-rw-r--r-- | tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.nix | 4 | ||||
-rw-r--r-- | tvix/eval/src/value/list.rs | 4 |
5 files changed, 27 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index 74215cd37c92..3598ac71f7db 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -75,6 +75,14 @@ fn pure_builtins() -> Vec<Builtin> { } Ok(Value::Integer(args[0].to_list()?.len() as i64)) }), + Builtin::new("head", 1, |args, vm| { + force!(vm, &args[0], xs, { + match xs.to_list()?.get(0) { + Some(x) => Ok(x.clone()), + None => Err(ErrorKind::IndexOutOfBounds { index: 0 }), + } + }) + }), Builtin::new("isAttrs", 1, |args, _| { Ok(Value::Bool(matches!(args[0], Value::Attrs(_)))) }), diff --git a/tvix/eval/src/errors.rs b/tvix/eval/src/errors.rs index 086cc9d9052c..a84c931d0a4e 100644 --- a/tvix/eval/src/errors.rs +++ b/tvix/eval/src/errors.rs @@ -25,6 +25,11 @@ pub enum ErrorKind { name: String, }, + // Attempted to index into a list beyond its boundaries. + IndexOutOfBounds { + index: usize, + }, + TypeError { expected: &'static str, actual: &'static str, @@ -123,6 +128,10 @@ impl Error { name ), + ErrorKind::IndexOutOfBounds { index } => { + format!("list index '{}' is out of bounds", index) + } + ErrorKind::TypeError { expected, actual } => format!( "expected value of type '{}', but found a '{}'", expected, actual @@ -208,6 +217,7 @@ to a missing value in the attribute set(s) included via `with`."#, ErrorKind::DuplicateAttrsKey { .. } => "E016", ErrorKind::ThunkForce(_) => "E017", ErrorKind::NotCoercibleToString { .. } => "E018", + ErrorKind::IndexOutOfBounds { .. } => "E019", ErrorKind::NotImplemented(_) => "E999", } } diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.exp new file mode 100644 index 000000000000..afe288459f2e --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.exp @@ -0,0 +1 @@ +[ "foo" 1 ] diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.nix new file mode 100644 index 000000000000..1741a7aac4bb --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-head.nix @@ -0,0 +1,4 @@ +[ + (builtins.head [ "foo" ]) + (builtins.head [ 1 2 3 ]) +] diff --git a/tvix/eval/src/value/list.rs b/tvix/eval/src/value/list.rs index da86fdda26ec..c00ddd4191ea 100644 --- a/tvix/eval/src/value/list.rs +++ b/tvix/eval/src/value/list.rs @@ -32,6 +32,10 @@ impl NixList { self.0.len() } + pub fn get(&self, i: usize) -> Option<&Value> { + self.0.get(i) + } + pub fn construct(count: usize, stack_slice: Vec<Value>) -> Self { debug_assert!( count == stack_slice.len(), |