From 541f17afb8b869f4f71781e47276cc77c4448330 Mon Sep 17 00:00:00 2001
From: Jayaram Kancherla <jayaram.kancherla@gmail.com>
Date: Thu, 25 Jun 2026 09:00:35 -0700
Subject: [PATCH 1/2] Implement save_rds for NumPy scalars

---
 CHANGELOG.md              |  1 +
 src/rds2py/save_atomic.py |  6 ++++++
 tests/test_atomics.py     | 30 ++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7854479..cc25e22 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - Read `symbols` registered in RDS objects.
 - Fixed an issue with S4 classes not properly saved as RDS files.
 - Implement `save_rds` generic for sparse matrix formats (csc, csr and coo).
+- Implement `save_rds` for NumPy scalars.
 
 ## Version 0.9.0 - 0.9.1
 
diff --git a/src/rds2py/save_atomic.py b/src/rds2py/save_atomic.py
index 1ecd09b..0d1f0ff 100644
--- a/src/rds2py/save_atomic.py
+++ b/src/rds2py/save_atomic.py
@@ -26,6 +26,12 @@ def _save_rds_primitives(x, path: Optional[str] = None):
     return x
 
 
+@save_rds.register(np.generic)
+def _save_rds_numpy_scalars(x: np.generic, path: Optional[str] = None):
+    return save_rds(x.item(), path=path)
+
+
+
 @save_rds.register(BooleanList)
 def _save_rds_booleanlist(x: BooleanList, path: Optional[str] = None):
     from .lib_rds_parser import write_rds as _write_rds_native
diff --git a/tests/test_atomics.py b/tests/test_atomics.py
index a4a31c2..e28da78 100644
--- a/tests/test_atomics.py
+++ b/tests/test_atomics.py
@@ -119,3 +119,33 @@ def test_save_names_directly():
     finally:
         if os.path.exists(path):
             os.unlink(path)
+
+
+def test_save_numpy_scalars():
+    import numpy as np
+    from rds2py import save_rds
+
+    # Test integer scalar
+    i_scalar = np.int32(42)
+    res_i = save_rds(i_scalar)
+    assert isinstance(res_i, int)
+    assert res_i == 42
+
+    # Test float scalar
+    f_scalar = np.float64(3.14)
+    res_f = save_rds(f_scalar)
+    assert isinstance(res_f, float)
+    assert res_f == 3.14
+
+    # Test bool scalar
+    b_scalar = np.bool_(True)
+    res_b = save_rds(b_scalar)
+    assert isinstance(res_b, bool)
+    assert res_b is True
+
+    # Test string scalar
+    s_scalar = np.str_("hello")
+    res_s = save_rds(s_scalar)
+    assert isinstance(res_s, str)
+    assert res_s == "hello"
+

From 5f113577dc896afab613efd583e8d22a4adabe2d Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 25 Jun 2026 16:01:03 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/rds2py/save_atomic.py | 1 -
 tests/test_atomics.py     | 1 -
 2 files changed, 2 deletions(-)

diff --git a/src/rds2py/save_atomic.py b/src/rds2py/save_atomic.py
index 0d1f0ff..5f0379f 100644
--- a/src/rds2py/save_atomic.py
+++ b/src/rds2py/save_atomic.py
@@ -31,7 +31,6 @@ def _save_rds_numpy_scalars(x: np.generic, path: Optional[str] = None):
     return save_rds(x.item(), path=path)
 
 
-
 @save_rds.register(BooleanList)
 def _save_rds_booleanlist(x: BooleanList, path: Optional[str] = None):
     from .lib_rds_parser import write_rds as _write_rds_native
diff --git a/tests/test_atomics.py b/tests/test_atomics.py
index e28da78..57d9176 100644
--- a/tests/test_atomics.py
+++ b/tests/test_atomics.py
@@ -148,4 +148,3 @@ def test_save_numpy_scalars():
     res_s = save_rds(s_scalar)
     assert isinstance(res_s, str)
     assert res_s == "hello"
-