Implement save_rds for NumPy scalars

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
 

src/rds2py/save_atomic.py

@@ -26,6 +26,11 @@ 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

tests/test_atomics.py

@@ -119,3 +119,32 @@ 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"