Reflect::try_compare draft

fyrox-core-derive/src/reflect.rs

@@ -443,6 +443,18 @@ fn gen_impl(
         }
     };
 
+    let try_compare = if ty_args.non_comparable {
+        quote! {
+            fn try_compare(&self, _other: &dyn Reflect) -> Option<bool> { None }
+        }
+    } else {
+        quote! {
+            fn try_compare(&self, other: &dyn Reflect) -> Option<bool> {
+                (other as &dyn Any).downcast_ref::<Self>().map(|other| other == self)
+            }
+        }
+    };
+
     let type_uuid_str = ty_args.type_uuid.as_str();
     let type_uuid = if ty_args.generics.params.is_empty() {
         quote! { uuid!(#type_uuid_str) }
@@ -494,6 +506,8 @@ fn gen_impl(
 
             #try_clone_box
 
+            #try_compare
+
             fn fields_ref(&self, func: &mut dyn FnMut(&[FieldRef])) {
                 #metadata_ref
             }

fyrox-core-derive/src/reflect/args.rs

@@ -63,6 +63,9 @@ pub struct TypeArgs {
     #[darling(default)]
     pub non_cloneable: bool,
 
+    #[darling(default)]
+    pub non_comparable: bool,
+
     #[darling(default)]
     pub clone_fn: Option<Path>,
 

fyrox-core/src/math/mod.rs

@@ -37,7 +37,7 @@ use fyrox_core_derive::{impl_reflect, impl_visit};
 
 impl_reflect!(
     #[reflect(type_uuid = "64ef33b7-d05a-4d8d-b0c7-99bcc919271f")]
-    pub struct Rect<T: Reflect + Copy> {}
+    pub struct Rect<T: Reflect + Copy + PartialEq> {}
 );
 
 impl<T> Visit for Rect<T>

fyrox-core/src/pool/handle.rs

@@ -207,6 +207,12 @@ impl<T: Reflect> Reflect for Handle<T> {
             None
         }
     }
+
+    fn try_compare(&self, other: &dyn Reflect) -> Option<bool> {
+        (other as &dyn std::any::Any)
+            .downcast_ref::<Self>()
+            .map(|other| other == self)
+    }
 }
 
 impl<T> Copy for Handle<T> {}

fyrox-core/src/pool/mod.rs

@@ -170,6 +170,12 @@ where
         Some(Box::new(self.clone()))
     }
 
+    fn try_compare(&self, other: &dyn Reflect) -> Option<bool> {
+        (other as &dyn std::any::Any)
+            .downcast_ref::<Self>()
+            .map(|other| other == self)
+    }
+
     #[inline]
     fn fields_ref(&self, func: &mut dyn FnMut(&[FieldRef])) {
         func(&[])

fyrox-core/src/reflect/impls.rs

@@ -334,6 +334,8 @@ macro_rules! impl_reflect_inner_mutability {
             Some(Box::new($clone))
         }
 
+
+
         fn fields_ref(&$self, func: &mut dyn FnMut(&[FieldRef])) {
             let guard = $acquire_lock_guard;
             func(&[{

fyrox-core/src/reflect/macros.rs

@@ -158,6 +158,12 @@ macro_rules! blank_reflect {
             Some(Box::new(self.clone()))
         }
 
+        fn try_compare(&self, other: &dyn Reflect) -> Option<bool> {
+            (other as &dyn std::any::Any)
+                .downcast_ref::<Self>()
+                .map(|other| other == self)
+        }
+
         fn fields_ref(&self, func: &mut dyn FnMut(&[$crate::reflect::FieldRef])) {
             func(&[])
         }

fyrox-core/src/reflect/mod.rs

@@ -53,6 +53,7 @@ pub mod prelude {
         TypeInfo,
     };
     pub use crate::uuid::{uuid, Uuid};
+    pub use std::any::Any;
 }
 
 #[inline]
@@ -175,6 +176,11 @@ pub trait Reflect: Any + Debug {
     /// [`None`] for non-cloneable objects.
     fn try_clone_box(&self) -> Option<Box<dyn Reflect>>;
 
+    /// Tries to compare this object with some other. The result is `Some(bool)` if the underlying
+    /// type implements [`PartialEq`] trait, `None` - otherwise or if the type is marked with
+    /// `#[reflect(non_comparable)]` attribute.
+    fn try_compare(&self, other: &dyn Reflect) -> Option<bool>;
+
     /// Calls the given closure with the reference to a slice that contains description for all
     /// fields in the object.
     fn fields_ref(&self, func: &mut dyn FnMut(&[FieldRef]));
@@ -1021,7 +1027,7 @@ mod test {
         },
     }
 
-    #[derive(Reflect, Clone, Default, Debug)]
+    #[derive(Reflect, Clone, Default, Debug, PartialEq)]
     #[reflect(type_uuid = "97718a85-3901-407e-9347-b684c0047743")]
     struct Foo {
         enum_field: InheritableVariable<Enum>,
@@ -1031,13 +1037,13 @@ mod test {
         hash_map: HashMap<String, Item>,
     }
 
-    #[derive(Reflect, Clone, Default, Debug)]
+    #[derive(Reflect, Clone, Default, Debug, PartialEq)]
     #[reflect(type_uuid = "9465ea72-dd27-43f3-8ccf-b634e4b2887f")]
     struct Item {
         payload: u32,
     }
 
-    #[derive(Reflect, Clone, Default, Debug)]
+    #[derive(Reflect, Clone, Default, Debug, PartialEq)]
     #[reflect(type_uuid = "8fb478ac-e4c4-4762-a43a-451147e6e509")]
     struct Bar {
         stuff: String,