Add string comparison support so that x.sort() works

asciidtype/asciidtype/src/asciidtype_main.c

@@ -22,7 +22,7 @@ PyInit__asciidtype_main(void)
         return NULL;
     }
 
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         return NULL;
     }
 

metadatadtype/metadatadtype/src/metadatadtype_main.c

@@ -21,7 +21,7 @@ PyInit__metadatadtype_main(void)
     if (_import_array() < 0) {
         return NULL;
     }
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         return NULL;
     }
 

mpfdtype/mpfdtype/src/mpfdtype_main.c

@@ -22,7 +22,7 @@ PyInit__mpfdtype_main(void)
     if (_import_array() < 0) {
         return NULL;
     }
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         return NULL;
     }
 

quaddtype/quaddtype/src/quaddtype_main.c

@@ -23,7 +23,7 @@ PyInit__quaddtype_main(void)
         return NULL;
 
     // Fail to init if the experimental DType API version 5 isn't supported
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         PyErr_SetString(PyExc_ImportError,
                         "Error encountered importing the experimental dtype API.");
         return NULL;

stringdtype/README.md

@@ -10,18 +10,26 @@ NumPy.
 Ensure Meson and NumPy are installed in the python environment you would like to use:
 
 ```
-$ python3 -m pip install meson meson-python numpy build patchelf
+$ python3 -m pip install meson meson-python build patchelf
 ```
 
-Build with meson, create a wheel, and install it
+It is important to have the latest development version of numpy installed.
+Nightly wheels work well for this purpose, and can be installed easily:
 
+```bash
+$ pip install -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
 ```
+
+Build with meson, create a wheel, and install it.
+
+```bash
 $ rm -r dist/
 $ meson build
 $ python -m build --wheel -Cbuilddir=build
-$ python -m pip install dist/asciidtype*.whl
 ```
 
-The `mesonpy` build backend for pip [does not currently support editable
-installs](https://github.com/mesonbuild/meson-python/issues/47), so `pip install
--e .` will not work.
+Or simply install directly, taking care to install without build isolation:
+
+```bash
+$ pip install -v . --no-build-isolation
+```

stringdtype/stringdtype/__init__.py

@@ -5,7 +5,6 @@
 from .scalar import StringScalar  # isort: skip
 from ._main import StringDType, _memory_usage
 
-
 __all__ = [
     "StringDType",
     "StringScalar",

stringdtype/stringdtype/src/casts.c

@@ -295,7 +295,7 @@ string_to_unicode_resolve_descriptors(PyObject *NPY_UNUSED(self),
 // codepoint for the next character, returning the size of the character in
 // bytes. Does not do any validation or error checking: assumes *c* is valid
 // utf-8
-static size_t
+size_t
 utf8_char_to_ucs4_code(unsigned char *c, Py_UCS4 *code)
 {
     if (c[0] <= 0x7F) {

stringdtype/stringdtype/src/casts.h

@@ -13,4 +13,7 @@
 PyArrayMethod_Spec **
 get_casts(void);
 
+size_t
+utf8_char_to_ucs4_code(unsigned char *, Py_UCS4 *);
+
 #endif /* _NPY_CASTS_H */

stringdtype/stringdtype/src/dtype.c

@@ -155,6 +155,16 @@ stringdtype_getitem(StringDTypeObject *descr, char **dataptr)
     return res;
 }
 
+// Implementation of PyArray_CompareFunc.
+// Compares unicode strings by their code points.
+int
+compare_strings(char **a, char **b, PyArrayObject *NPY_UNUSED(arr))
+{
+    ss *ss_a = (ss *)*a;
+    ss *ss_b = (ss *)*b;
+    return strcmp(ss_a->buf, ss_b->buf);
+}
+
 static StringDTypeObject *
 stringdtype_ensure_canonical(StringDTypeObject *self)
 {
@@ -170,6 +180,7 @@ static PyType_Slot StringDType_Slots[] = {
         {NPY_DT_setitem, &stringdtype_setitem},
         {NPY_DT_getitem, &stringdtype_getitem},
         {NPY_DT_ensure_canonical, &stringdtype_ensure_canonical},
+        {NPY_DT_PyArray_ArrFuncs_compare, &compare_strings},
         {0, NULL}};
 
 static PyObject *

stringdtype/stringdtype/src/main.c

@@ -90,7 +90,7 @@ PyInit__main(void)
     if (_import_array() < 0) {
         return NULL;
     }
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         return NULL;
     }
 

stringdtype/tests/test_stringdtype.py

@@ -161,3 +161,23 @@ def test_pickle(string_list):
     assert res[1] == dtype
 
     os.remove(f.name)
+
+
+@pytest.mark.parametrize(
+    "strings",
+    [
+        ["left", "right", "leftovers", "righty", "up", "down"],
+        ["🤣🤣", "🤣", "📵", "😰"],
+        ["🚜", "🙃", "😾"],
+        ["😹", "🚠", "🚌"],
+        ["A¢☃€ 😊", " A☃€¢😊", "☃€😊 A¢", "😊☃A¢ €"],
+    ],
+)
+def test_sort(strings):
+    """Test that sorting matches python's internal sorting."""
+    arr = np.array(strings, dtype=StringDType())
+    arr_sorted = np.array(sorted(strings), dtype=StringDType())
+
+    np.random.default_rng().shuffle(arr)
+    arr.sort()
+    np.testing.assert_array_equal(arr, arr_sorted)

unytdtype/unytdtype/src/unytdtype_main.c

@@ -21,7 +21,7 @@ PyInit__unytdtype_main(void)
     if (_import_array() < 0) {
         return NULL;
     }
-    if (import_experimental_dtype_api(7) < 0) {
+    if (import_experimental_dtype_api(8) < 0) {
         return NULL;
     }