bpo-37128: Add math.perm(). (GH-13731)

1 files changed, 36 insertions, 1 deletions

diff --git a/Modules/clinic/mathmodule.c.h b/Modules/clinic/mathmodule.c.h
index 92ec4be..0efe5cc 100644
--- a/Modules/clinic/mathmodule.c.h
+++ b/Modules/clinic/mathmodule.c.h
@@ -638,6 +638,41 @@ exit:
     return return_value;
 }
 
+PyDoc_STRVAR(math_perm__doc__,
+"perm($module, n, k, /)\n"
+"--\n"
+"\n"
+"Number of ways to choose k items from n items without repetition and with order.\n"
+"\n"
+"It is mathematically equal to the expression n! / (n - k)!.\n"
+"\n"
+"Raises TypeError if the arguments are not integers.\n"
+"Raises ValueError if the arguments are negative or if k > n.");
+
+#define MATH_PERM_METHODDEF    \
+    {"perm", (PyCFunction)(void(*)(void))math_perm, METH_FASTCALL, math_perm__doc__},
+
+static PyObject *
+math_perm_impl(PyObject *module, PyObject *n, PyObject *k);
+
+static PyObject *
+math_perm(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
+{
+    PyObject *return_value = NULL;
+    PyObject *n;
+    PyObject *k;
+
+    if (!_PyArg_CheckPositional("perm", nargs, 2, 2)) {
+        goto exit;
+    }
+    n = args[0];
+    k = args[1];
+    return_value = math_perm_impl(module, n, k);
+
+exit:
+    return return_value;
+}
+
 PyDoc_STRVAR(math_comb__doc__,
 "comb($module, n, k, /)\n"
 "--\n"
@@ -674,4 +709,4 @@ math_comb(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=6709521e5e1d90ec input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a82b0e705b6d0ec0 input=a9049054013a1b77]*/