From 6229ae26e6a98a0a4a2adb66d6e1a3f7305e6c41 Mon Sep 17 00:00:00 2001
From: Jim Pivarski <jpivarski@gmail.com>
Date: Wed, 27 Dec 2023 15:45:16 -0600
Subject: [PATCH] Data type functions: astype.

---
 src/ragged/common/__init__.py   |  5 +++++
 src/ragged/common/_datatype.py  | 38 +++++++++++++++++++++++++++++++++
 src/ragged/v202212/__init__.py  |  5 +++++
 src/ragged/v202212/_datatype.py | 15 +++++++++++++
 4 files changed, 63 insertions(+)
 create mode 100644 src/ragged/common/_datatype.py
 create mode 100644 src/ragged/v202212/_datatype.py

diff --git a/src/ragged/common/__init__.py b/src/ragged/common/__init__.py
index 84a1624..e94a79c 100644
--- a/src/ragged/common/__init__.py
+++ b/src/ragged/common/__init__.py
@@ -27,6 +27,9 @@
     zeros,
     zeros_like,
 )
+from ._datatype import (
+    astype,
+)
 from ._obj import array
 
 __all__ = [
@@ -47,6 +50,8 @@
     "triu",
     "zeros",
     "zeros_like",
+    # _datatype
+    "astype",
     # _obj
     "array",
 ]
diff --git a/src/ragged/common/_datatype.py b/src/ragged/common/_datatype.py
new file mode 100644
index 0000000..6dcaa84
--- /dev/null
+++ b/src/ragged/common/_datatype.py
@@ -0,0 +1,38 @@
+# BSD 3-Clause License; see https://github.com/scikit-hep/ragged/blob/main/LICENSE
+
+"""
+https://data-apis.org/array-api/latest/API_specification/data_type_functions.html
+"""
+
+from __future__ import annotations
+
+from ._obj import array
+from ._typing import (
+    Dtype,
+)
+
+
+def astype(x: array, dtype: Dtype, /, *, copy: bool = True) -> array:
+    """
+    Copies an array to a specified data type irrespective of type promotion rules.
+
+    Args:
+        x: Array to cast.
+        dtype: Desired data type.
+        copy: Specifies whether to copy an array when the specified `dtype`
+            matches the data type of the input array `x`. If `True`, a newly
+            allocated array is always returned. If `False` and the specified
+            `dtype` matches the data type of the input array, the input array
+            is returned; otherwise, a newly allocated array is returned.
+
+    Returns:
+        An array having the specified data type. The returned array has the
+        same `shape` as `x`.
+
+    https://data-apis.org/array-api/latest/API_specification/generated/array_api.astype.html
+    """
+
+    assert x, "TODO"
+    assert dtype, "TODO"
+    assert copy, "TODO"
+    assert False, "TODO"
diff --git a/src/ragged/v202212/__init__.py b/src/ragged/v202212/__init__.py
index 5906977..7e1ec84 100644
--- a/src/ragged/v202212/__init__.py
+++ b/src/ragged/v202212/__init__.py
@@ -29,6 +29,9 @@
     zeros,
     zeros_like,
 )
+from ._datatype import (
+    astype,
+)
 from ._obj import array
 
 __all__ = [
@@ -49,6 +52,8 @@
     "triu",
     "zeros",
     "zeros_like",
+    # _datatype
+    "astype",
     # _obj
     "array",
 ]
diff --git a/src/ragged/v202212/_datatype.py b/src/ragged/v202212/_datatype.py
new file mode 100644
index 0000000..eff6f05
--- /dev/null
+++ b/src/ragged/v202212/_datatype.py
@@ -0,0 +1,15 @@
+# BSD 3-Clause License; see https://github.com/scikit-hep/ragged/blob/main/LICENSE
+
+"""
+https://data-apis.org/array-api/2022.12/API_specification/creation_functions.html
+"""
+
+from __future__ import annotations
+
+from ..common._datatype import (
+    astype,
+)
+
+__all__ = [
+    "astype",
+]