Add dtype() top-level function for convenience

Author: aldanor

src/array.rs

@@ -168,7 +168,7 @@ impl<T, D> PyArray<T, D> {
     /// pyo3::Python::with_gil(|py| {
     ///    let array = numpy::PyArray::from_vec(py, vec![1, 2, 3i32]);
     ///    let dtype = array.dtype();
-    ///    assert!(dtype.is_equiv_to(numpy::PyArrayDescr::of::<i32>(py)));
+    ///    assert!(dtype.is_equiv_to(numpy::dtype::<i32>(py)));
     /// });
     /// ```
     pub fn dtype(&self) -> &crate::PyArrayDescr {

src/dtype.rs

@@ -20,7 +20,7 @@ pub use num_complex::{Complex32, Complex64};
 ///         .unwrap()
 ///         .downcast()
 ///         .unwrap();
-///     assert!(dtype.is_equiv_to(numpy::PyArrayDescr::of::<f64>(py)));
+///     assert!(dtype.is_equiv_to(numpy::dtype::<f64>(py)));
 /// });
 /// ```
 pub struct PyArrayDescr(PyAny);
@@ -39,6 +39,11 @@ unsafe fn arraydescr_check(op: *mut ffi::PyObject) -> c_int {
     )
 }
 
+/// Returns the type descriptor ("dtype") for a registered type.
+pub fn dtype<T: Element>(py: Python) -> &PyArrayDescr {
+    T::get_dtype(py)
+}
+
 impl PyArrayDescr {
     /// Returns `self` as `*mut PyArray_Descr`.
     pub fn as_dtype_ptr(&self) -> *mut PyArray_Descr {
@@ -72,7 +77,7 @@ impl PyArrayDescr {
         Self::from_npy_type(py, NPY_TYPES::NPY_OBJECT)
     }
 
-    /// Returns the type descriptor for a registered type.
+    /// Returns the type descriptor ("dtype") for a registered type.
     pub fn of<T: Element>(py: Python) -> &Self {
         T::get_dtype(py)
     }
@@ -254,12 +259,12 @@ unsafe impl Element for PyObject {
 mod tests {
     use std::mem::size_of;
 
-    use super::{Complex32, Complex64, Element, PyArrayDescr};
+    use super::{dtype, Complex32, Complex64, Element};
 
     #[test]
     fn test_dtype_names() {
         fn type_name<T: Element>(py: pyo3::Python) -> &str {
-            PyArrayDescr::of::<T>(py).get_type().name().unwrap()
+            dtype::<T>(py).get_type().name().unwrap()
         }
         pyo3::Python::with_gil(|py| {
             assert_eq!(type_name::<bool>(py), "bool_");

src/lib.rs

@@ -46,7 +46,7 @@ pub use crate::array::{
     PyArray6, PyArrayDyn,
 };
 pub use crate::convert::{IntoPyArray, NpyIndex, ToNpyDims, ToPyArray};
-pub use crate::dtype::{Complex32, Complex64, Element, PyArrayDescr};
+pub use crate::dtype::{dtype, Complex32, Complex64, Element, PyArrayDescr};
 pub use crate::error::{DimensionalityError, FromVecError, NotContiguousError, TypeError};
 pub use crate::npyffi::{PY_ARRAY_API, PY_UFUNC_API};
 pub use crate::npyiter::{

tests/array.rs

@@ -249,7 +249,7 @@ fn dtype_from_py() {
             .downcast()
             .unwrap();
         assert_eq!(&format!("{:?}", dtype), "dtype('uint32')");
-        assert!(dtype.is_equiv_to(numpy::PyArrayDescr::of::<u32>(py)));
+        assert!(dtype.is_equiv_to(numpy::dtype::<u32>(py)));
     })
 }