DLPack memoryview support

Author: wjakob

docs/api_extra.rst

@@ -1104,6 +1104,10 @@ convert into an equivalent representation in one of the following frameworks:
 
 .. cpp:class:: cupy
 
+.. cpp:class:: memview
+
+   Builtin Python ``memoryview`` for CPU-resident data.
+
 Eigen convenience type aliases
 ------------------------------
 

include/nanobind/ndarray.h

@@ -85,6 +85,7 @@ NB_FRAMEWORK(pytorch, 2, "torch.Tensor");
 NB_FRAMEWORK(tensorflow, 3, "tensorflow.python.framework.ops.EagerTensor");
 NB_FRAMEWORK(jax, 4, "jaxlib.xla_extension.DeviceArray");
 NB_FRAMEWORK(cupy, 5, "cupy.ndarray");
+NB_FRAMEWORK(memview, 6, "memoryview");
 
 NAMESPACE_BEGIN(device)
 NB_DEVICE(none, 0); NB_DEVICE(cpu, 1); NB_DEVICE(cuda, 2);

src/nb_ndarray.cpp

@@ -765,7 +765,7 @@ PyObject *ndarray_export(ndarray_handle *th, int framework,
     object o;
     if (copy && framework == no_framework::value && th->self) {
         o = borrow(th->self);
-    } else if (framework == numpy::value || framework == jax::value) {
+    } else if (framework == numpy::value || framework == jax::value || framework == memview::value) {
         nb_ndarray *h = PyObject_New(nb_ndarray, nd_ndarray_tp());
         if (!h)
             return nullptr;
@@ -784,6 +784,8 @@ PyObject *ndarray_export(ndarray_handle *th, int framework,
                 .attr("array")(o, arg("copy") = copy)
                 .release()
                 .ptr();
+        } else if (framework == memview::value) {
+            return PyMemoryView_FromObject(o.ptr());
         } else {
             const char *pkg_name;
             switch (framework) {