Move the scalar back to python

Author: ngoldbaum

stringdtype/meson.build

@@ -30,13 +30,12 @@ srcs = [
   'stringdtype/src/static_string.h',
   'stringdtype/src/umath.c',
   'stringdtype/src/umath.h',
-  'stringdtype/src/scalar.h',
-  'stringdtype/src/scalar.c',
 ]
 
 py.install_sources(
   [
     'stringdtype/__init__.py',
+    'stringdtype/scalar.py'
   ],
   subdir: 'stringdtype'
 )

stringdtype/stringdtype/__init__.py

@@ -2,7 +2,8 @@
 
 """
 
-from ._main import StringDType, StringScalar, _memory_usage
+from .scalar import StringScalar  # isort: skip
+from ._main import StringDType, _memory_usage
 
 __all__ = [
     "StringDType",

stringdtype/stringdtype/scalar.py

@@ -0,0 +1,5 @@
+"""A scalar type needed by the dtype machinery."""
+
+
+class StringScalar(str):
+    pass

stringdtype/stringdtype/src/dtype.c

@@ -1,9 +1,10 @@
 #include "dtype.h"
 
 #include "casts.h"
-#include "scalar.h"
 #include "static_string.h"
 
+PyTypeObject *StringScalar_Type = NULL;
+
 /*
  * Internal helper to create new instances
  */
@@ -63,7 +64,7 @@ static PyArray_Descr *
 string_discover_descriptor_from_pyobject(PyArray_DTypeMeta *NPY_UNUSED(cls),
                                          PyObject *obj)
 {
-    if (Py_TYPE(obj) != &StringScalar_Type) {
+    if (Py_TYPE(obj) != StringScalar_Type) {
         PyErr_SetString(PyExc_TypeError,
                         "Can only store StringScalar in a StringDType array.");
         return NULL;
@@ -83,7 +84,7 @@ get_value(PyObject *scalar)
     PyTypeObject *scalar_type = Py_TYPE(scalar);
     // FIXME: handle bytes too
     if ((scalar_type == &PyUnicode_Type) ||
-        (scalar_type == &StringScalar_Type)) {
+        (scalar_type == StringScalar_Type)) {
         // attempt to decode as UTF8
         ret_bytes = PyUnicode_AsUTF8String(scalar);
         if (ret_bytes == NULL) {
@@ -394,7 +395,7 @@ init_string_dtype(void)
     PyArrayMethod_Spec **casts = get_casts();
 
     PyArrayDTypeMeta_Spec StringDType_DTypeSpec = {
-            .typeobj = &StringScalar_Type,
+            .typeobj = StringScalar_Type,
             .slots = StringDType_Slots,
             .casts = casts,
     };

stringdtype/stringdtype/src/dtype.h

@@ -18,6 +18,7 @@ typedef struct {
 } StringDTypeObject;
 
 extern PyArray_DTypeMeta StringDType;
+extern PyTypeObject *StringScalar_Type;
 
 StringDTypeObject *
 new_stringdtype_instance(void);

stringdtype/stringdtype/src/main.c

@@ -6,7 +6,6 @@
 #include "numpy/experimental_dtype_api.h"
 
 #include "dtype.h"
-#include "scalar.h"
 #include "static_string.h"
 #include "umath.h"
 
@@ -101,7 +100,16 @@ PyInit__main(void)
         return NULL;
     }
 
-    if (init_stringdtype_scalar() < 0) {
+    PyObject *mod = PyImport_ImportModule("stringdtype");
+    if (mod == NULL) {
+        goto error;
+    }
+
+    StringScalar_Type =
+            (PyTypeObject *)PyObject_GetAttrString(mod, "StringScalar");
+    Py_DECREF(mod);
+
+    if (StringScalar_Type == NULL) {
         goto error;
     }
 
@@ -115,13 +123,6 @@ PyInit__main(void)
         goto error;
     }
 
-    Py_INCREF((PyObject *)&StringScalar_Type);
-    if (PyModule_AddObject(m, "StringScalar", (PyObject *)&StringScalar_Type) <
-        0) {
-        Py_DECREF((PyObject *)&StringScalar_Type);
-        goto error;
-    }
-
     if (init_ufuncs() < 0) {
         goto error;
     }