3 files changed, 16 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index 0b19a89aa316..cabdaf0070c7 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -100,6 +100,11 @@ fn pure_builtins() -> Vec<Builtin> {
 
             Ok(Value::List(NixList::construct(output.len(), output)))
         }),
+        Builtin::new("baseNameOf", &[true], |args: Vec<Value>, vm: &mut VM| {
+            let s = args[0].coerce_to_string(CoercionKind::Weak, vm)?;
+            let result: String = s.rsplit_once('/').map(|(_, x)| x).unwrap_or(&s).into();
+            Ok(result.into())
+        }),
         Builtin::new("bitAnd", &[true, true], |args: Vec<Value>, _: &mut VM| {
             Ok(Value::Integer(args[0].as_int()? & args[1].as_int()?))
         }),
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.exp
new file mode 100644
index 000000000000..60a773f4af69
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.exp
@@ -0,0 +1 @@
+[ "bar" "foo" "" "bar" "." "" "" "" ]
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.nix
new file mode 100644
index 000000000000..bc59613f541d
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-basenameof.nix
@@ -0,0 +1,10 @@
+[
+  (builtins.baseNameOf /foo/bar)
+  (builtins.baseNameOf "foo")
+  (builtins.baseNameOf "foo///")
+  (builtins.baseNameOf "foo/bar")
+  (builtins.baseNameOf "./.")
+  (builtins.baseNameOf "")
+  (builtins.baseNameOf /.)
+  (builtins.toString (builtins.baseNameOf /.))
+]