Add mapping property to dict_keys

Author: seryoungshim17

vm/src/builtins/dict.rs

@@ -1,6 +1,6 @@
 use super::{
     set::PySetInner, IterStatus, PositionIterInternal, PyBaseExceptionRef, PyGenericAlias, PySet,
-    PyStrRef, PyTupleRef, PyType, PyTypeRef,
+    PyStrRef, PyTupleRef, PyType, PyTypeRef, PyMappingProxy,
 };
 use crate::{
     builtins::{
@@ -1041,6 +1041,11 @@ impl PyDictKeys {
     fn contains(zelf: PyRef<Self>, key: PyObjectRef, vm: &VirtualMachine) -> PyResult<bool> {
         zelf.dict().contains(key, vm)
     }
+
+    #[pyproperty]
+    fn mapping(zelf: PyRef<Self>) -> PyMappingProxy {
+        PyMappingProxy::from(zelf.dict().clone())
+    }
 }
 impl Unconstructible for PyDictKeys {}
 

vm/src/builtins/mappingproxy.rs

@@ -1,4 +1,4 @@
-use super::{PyDict, PyGenericAlias, PyList, PyTuple, PyType, PyTypeRef};
+use super::{PyDict, PyGenericAlias, PyList, PyTuple, PyType, PyTypeRef, PyDictRef};
 use crate::{
     class::PyClassImpl,
     convert::ToPyObject,
@@ -34,6 +34,22 @@ impl PyMappingProxy {
     }
 }
 
+impl From<PyTypeRef> for PyMappingProxy {
+    fn from(dict: PyTypeRef) -> Self {
+        Self {
+            mapping: MappingProxyInner::Class(dict),
+        }
+    }
+}
+
+impl From<PyDictRef> for PyMappingProxy {
+    fn from(dict: PyDictRef) -> Self {
+        Self { 
+            mapping: MappingProxyInner::Mapping(ArgMapping::from_dict_exact(dict)),
+        }
+    }
+}
+
 impl Constructor for PyMappingProxy {
     type Args = PyObjectRef;