bpo-39573: Add Py_IS_TYPE macro

Author: corona10

Doc/c-api/structures.rst

@@ -70,6 +70,17 @@ the definition of all other Python objects.
       (((PyObject*)(o))->ob_type)
 
 
+.. c:macro:: Py_IS_TYPE(o, type)
+
+   This macro is used to check whether the type of object *o* is the *type*.
+   It expands to::
+
+      (Py_TYPE(o) == type)
+
+
+   .. versionadded:: 3.9
+
+
 .. c:function:: void Py_SET_TYPE(PyObject *o, PyTypeObject *type)
 
    Set the object *o* type to *type*.

Include/object.h

@@ -123,6 +123,11 @@ typedef struct {
 #define Py_TYPE(ob)             (_PyObject_CAST(ob)->ob_type)
 #define Py_SIZE(ob)             (_PyVarObject_CAST(ob)->ob_size)
 
+static inline int _Py_IS_TYPE(PyObject *ob, PyTypeObject *type) {
+    return ob->ob_type == type;
+}
+#define Py_IS_TYPE(ob, type) _Py_IS_TYPE(_PyObject_CAST(ob), type)
+
 static inline void _Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
     ob->ob_refcnt = refcnt;
 }

Misc/NEWS.d/next/Core and Builtins/2020-02-13-01-30-22.bpo-39573.uTFj1m.rst

@@ -0,0 +1,2 @@
+Add :c:macro:`Py_IS_TYPE` macro to check whether the type of object *o* is
+the *type*.