docs(tvix/eval): document attribute set related opcodes r/6570

Change-Id: Ib98a9fe8c9aa3f0e61c27d10285c0926cda7a969
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7979
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/tvix/eval/src/opcode.rs b/tvix/eval/src/opcode.rs
index a6c59278d286..9eb8418d89b1 100644
--- a/tvix/eval/src/opcode.rs
+++ b/tvix/eval/src/opcode.rs
@@ -128,9 +128,20 @@ pub enum OpCode {
     /// Note that this takes the count of *pairs*, not the number of *stack values* - the actual
     /// number of values popped off the stack will be twice the argument to this op
     OpAttrs(Count),
+    /// Merge the attribute set at {2} into the attribute set at {1},
+    /// and leave the new set at the top of the stack.
     OpAttrsUpdate,
+
+    /// Select the attribute with the name at {1} from the set at {2}.
     OpAttrsSelect,
+
+    /// Select the attribute with the name at {1} from the set at {2}, but leave
+    /// a `Value::AttrNotFound` in the stack instead of failing if it is
+    /// missing.
     OpAttrsTrySelect,
+
+    /// Check for the presence of the attribute with the name at {1} in the set
+    /// at {2}.
     OpHasAttr,
 
     /// Throw an error if the attribute set at the top of the stack has any attributes