PyClassImpl for PyClassMethod

youknowone · youknowone · commit b720681c7b68 · 2019-05-11T05:30:27.000+09:00
diff --git a/vm/src/obj/objclassmethod.rs b/vm/src/obj/objclassmethod.rs
@@ -1,7 +1,28 @@
 use super::objtype::PyClassRef;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
+/// classmethod(function) -> method
+///
+/// Convert a function to be a class method.
+///
+/// A class method receives the class as implicit first argument,
+/// just like an instance method receives the instance.
+/// To declare a class method, use this idiom:
+///
+///   class C:
+///       @classmethod
+///       def f(cls, arg1, arg2, ...):
+///           ...
+///
+/// It can be called either on the class (e.g. C.f()) or on an instance
+/// (e.g. C().f()).  The instance is ignored except for its class.
+/// If a class method is called for a derived class, the derived class
+/// object is passed as the implied first argument.
+///
+/// Class methods are different than C++ or Java static methods.
+/// If you want those, see the staticmethod builtin.
+#[pyclass]
 #[derive(Clone, Debug)]
 pub struct PyClassMethod {
     pub callable: PyObjectRef,
@@ -16,7 +37,9 @@ impl PyValue for PyClassMethod {
     }
 }
 
-impl PyClassMethodRef {
+#[pyimpl]
+impl PyClassMethod {
+    #[pymethod(name = "__new__")]
     fn new(
         cls: PyClassRef,
         callable: PyObjectRef,
@@ -28,17 +51,14 @@ impl PyClassMethodRef {
         .into_ref_with_type(vm, cls)
     }
 
-    fn get(self, _inst: PyObjectRef, owner: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+    #[pymethod(name = "__get__")]
+    fn get(&self, _inst: PyObjectRef, owner: PyObjectRef, vm: &VirtualMachine) -> PyResult {
         Ok(vm
             .ctx
             .new_bound_method(self.callable.clone(), owner.clone()))
     }
 }
 
 pub fn init(context: &PyContext) {
-    let classmethod_type = &context.classmethod_type;
-    extend_class!(context, classmethod_type, {
-        "__get__" => context.new_rustfunc(PyClassMethodRef::get),
-        "__new__" => context.new_rustfunc(PyClassMethodRef::new)
-    });
+    PyClassMethod::extend_class(context, &context.classmethod_type);
 }
