Merge pull request #832 from gilescope/macro

Need to be able to create structs via macro_rules

Author: messense

pyo3-macros-backend/src/pyclass.rs

@@ -7,7 +7,7 @@ use crate::attributes::{
 use crate::deprecations::Deprecations;
 use crate::pyimpl::PyClassMethodsType;
 use crate::pymethod::{impl_py_getter_def, impl_py_setter_def, PropertyType};
-use crate::utils;
+use crate::utils::{self, unwrap_group};
 use proc_macro2::{Span, TokenStream};
 use quote::quote;
 use syn::ext::IdentExt;
@@ -93,7 +93,7 @@ impl PyClassArgs {
                 // We allow arbitrary expressions here so you can e.g. use `8*64`
                 self.freelist = Some(syn::Expr::clone(right));
             }
-            "name" => match &**right {
+            "name" => match unwrap_group(&**right) {
                 syn::Expr::Lit(syn::ExprLit {
                     lit: syn::Lit::Str(lit),
                     ..
@@ -114,7 +114,7 @@ impl PyClassArgs {
                 }
                 _ => expected!("type name (e.g. \"Name\")"),
             },
-            "extends" => match &**right {
+            "extends" => match unwrap_group(&**right) {
                 syn::Expr::Path(exp) => {
                     self.base = syn::TypePath {
                         path: exp.path.clone(),
@@ -124,7 +124,7 @@ impl PyClassArgs {
                 }
                 _ => expected!("type path (e.g., my_mod::BaseClass)"),
             },
-            "module" => match &**right {
+            "module" => match unwrap_group(&**right) {
                 syn::Expr::Lit(syn::ExprLit {
                     lit: syn::Lit::Str(lit),
                     ..

pyo3-macros-backend/src/utils.rs

@@ -117,3 +117,10 @@ pub fn ensure_not_async_fn(sig: &syn::Signature) -> syn::Result<()> {
     };
     Ok(())
 }
+
+pub fn unwrap_group(mut expr: &syn::Expr) -> &syn::Expr {
+    while let syn::Expr::Group(g) = expr {
+        expr = &*g.expr;
+    }
+    expr
+}

tests/test_macros.rs

@@ -0,0 +1,91 @@
+//! Ensure that pyo3 macros can be used inside macro_rules!
+
+use pyo3::prelude::*;
+use pyo3::wrap_pyfunction;
+
+#[macro_use]
+mod common;
+
+macro_rules! make_struct_using_macro {
+    // Ensure that one doesn't need to fall back on the escape type: tt
+    // in order to macro create pyclass.
+    ($class_name:ident, $py_name:literal) => {
+        #[pyclass(name=$py_name)]
+        struct $class_name {}
+    };
+}
+
+make_struct_using_macro!(MyBaseClass, "MyClass");
+
+macro_rules! set_extends_via_macro {
+    ($class_name:ident, $base_class:path) => {
+        // Try and pass a variable into the extends parameter
+        #[pyclass(extends=$base_class)]
+        struct $class_name {}
+    };
+}
+
+set_extends_via_macro!(MyClass2, MyBaseClass);
+
+//
+// Check that pyfunctiona nd text_signature can be called with macro arguments.
+//
+
+macro_rules! fn_macro {
+    ($sig:literal, $a_exp:expr, $b_exp:expr, $c_exp: expr) => {
+        // Try and pass a variable into the extends parameter
+        #[pyfunction($a_exp, $b_exp, "*", $c_exp)]
+        #[pyo3(text_signature = $sig)]
+        fn my_function_in_macro(a: i32, b: Option<i32>, c: i32) {
+            let _ = (a, b, c);
+        }
+    };
+}
+
+fn_macro!("(a, b=None, *, c=42)", a, b = "None", c = 42);
+
+macro_rules! property_rename_via_macro {
+    ($prop_name:ident) => {
+        #[pyclass]
+        struct ClassWithProperty {
+            member: u64,
+        }
+
+        #[pymethods]
+        impl ClassWithProperty {
+            #[getter($prop_name)]
+            fn get_member(&self) -> u64 {
+                self.member
+            }
+
+            #[setter($prop_name)]
+            fn set_member(&mut self, member: u64) {
+                self.member = member;
+            }
+        }
+    };
+}
+
+property_rename_via_macro!(my_new_property_name);
+
+#[test]
+fn test_macro_rules_interactions() {
+    Python::with_gil(|py| {
+        let my_base = py.get_type::<MyBaseClass>();
+        py_assert!(py, my_base, "my_base.__name__ == 'MyClass'");
+
+        let my_func = wrap_pyfunction!(my_function_in_macro, py).unwrap();
+        py_assert!(
+            py,
+            my_func,
+            "my_func.__text_signature__ == '(a, b=None, *, c=42)'"
+        );
+
+        let renamed_prop = py.get_type::<ClassWithProperty>();
+        py_assert!(
+            py,
+            renamed_prop,
+            "hasattr(renamed_prop, 'my_new_property_name')"
+        );
+    });
+}