about summary refs log tree commit diff
path: root/tvix/eval/src/value/mod.rs
diff options
context:
space:
mode:
authorVincent Ambo <mail@tazj.in>2022-08-10T18·01+0300
committertazjin <tazjin@tvl.su>2022-08-25T11·34+0000
commit058e77bab20db90347ce1d91c41076ef56b61b26 (patch)
tree95198e36be78d26ce14bf40cb0a5cfb4d536cce6 /tvix/eval/src/value/mod.rs
parentfa2d250d1a65ba3bf8522fdbbe72dca21fa7ee66 (diff)
feat(tvix/eval): implement attrset update (`//`) operator r/4475
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
Diffstat (limited to 'tvix/eval/src/value/mod.rs')
-rw-r--r--tvix/eval/src/value/mod.rs10
1 files changed, 10 insertions, 0 deletions
diff --git a/tvix/eval/src/value/mod.rs b/tvix/eval/src/value/mod.rs
index 0a430ae08cb3..2a89f1c35890 100644
--- a/tvix/eval/src/value/mod.rs
+++ b/tvix/eval/src/value/mod.rs
@@ -71,6 +71,16 @@ impl Value {
             }),
         }
     }
+
+    pub fn as_attrs(self) -> EvalResult<Rc<NixAttrs>> {
+        match self {
+            Value::Attrs(s) => Ok(s),
+            other => Err(Error::TypeError {
+                expected: "set",
+                actual: other.type_of(),
+            }),
+        }
+    }
 }
 
 impl Display for Value {