props: add type peeking to ron, support arbitrary property types

assets/scene/load_scene_example.scn

@@ -1,6 +1,6 @@
 [
     (
-        entity: 3072676124,
+        entity: 1279729879,
         components: [
             {
                 "type": "load_scene::Test",
@@ -10,7 +10,7 @@
         ],
     ),
     (
-        entity: 3949176536,
+        entity: 1639302665,
         components: [
             {
                 "type": "load_scene::Test",

crates/bevy_property/Cargo.toml

@@ -9,4 +9,5 @@ edition = "2018"
 [dependencies]
 serde = "1"
 erased-serde = "0.3"
-bevy_property_derive = { path = "bevy_property_derive" }
+bevy_property_derive = { path = "bevy_property_derive" }
+ron = { path = "../ron" }

crates/bevy_property/src/dynamic_properties.rs

@@ -1,10 +1,13 @@
-use crate::{AsProperties, Properties, Property, PropertyIter, PropertyVal};
-use serde::{
-    de::{self, MapAccess, Visitor},
-    ser::SerializeMap,
-    Deserialize, Serialize,
+use crate::{
+    AsProperties, Properties, Property, PropertyIter, PropertyTypeRegistration,
+    PropertyTypeRegistry, PropertyVal,
 };
-use std::{any::Any, borrow::Cow, collections::HashMap};
+use serde::{
+    de::{self, DeserializeSeed, MapAccess, Visitor},
+    ser::SerializeMap,
+    Serialize,
+};
+use std::{any::Any, borrow::Cow, cell::RefCell, collections::HashMap, rc::Rc};
 
 #[derive(Default)]
 pub struct DynamicProperties {
@@ -100,14 +103,22 @@ impl Serialize for DynamicProperties {
     }
 }
 
-impl<'de> Deserialize<'de> for DynamicProperties {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+pub struct DynamicPropertiesDeserializer<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for DynamicPropertiesDeserializer<'a> {
+    type Value = DynamicProperties;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
     where
         D: serde::Deserializer<'de>,
     {
         let mut dynamic_properties = DynamicProperties::default();
         deserializer.deserialize_map(PropMapVisiter {
             dynamic_properties: &mut dynamic_properties,
+            property_type_registry: self.property_type_registry,
+            current_type_name: self.current_type_name,
         })?;
 
         Ok(dynamic_properties)
@@ -116,6 +127,8 @@ impl<'de> Deserialize<'de> for DynamicProperties {
 
 struct PropMapVisiter<'a> {
     dynamic_properties: &'a mut DynamicProperties,
+    property_type_registry: &'a PropertyTypeRegistry,
+    current_type_name: Rc<RefCell<Option<String>>>,
 }
 
 impl<'a, 'de> Visitor<'de> for PropMapVisiter<'a> {
@@ -133,7 +146,10 @@ impl<'a, 'de> Visitor<'de> for PropMapVisiter<'a> {
             if &key == "type" {
                 type_name = Some(map.next_value()?);
             } else {
-                let prop = map.next_value()?;
+                let prop = map.next_value_seed(MapValueDeserializer {
+                    property_type_registry: self.property_type_registry,
+                    current_type_name: self.current_type_name.clone(),
+                })?;
                 self.dynamic_properties.set_box(&key, prop);
             }
         }
@@ -144,18 +160,50 @@ impl<'a, 'de> Visitor<'de> for PropMapVisiter<'a> {
     }
 }
 
-impl<'de> Deserialize<'de> for Box<dyn Property> {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+pub struct MapValueDeserializer<'a> {
+    property_type_registry: &'a PropertyTypeRegistry,
+    current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for MapValueDeserializer<'a> {
+    type Value = Box<dyn Property>;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
     where
         D: serde::Deserializer<'de>,
     {
-        deserializer.deserialize_any(AnyPropVisiter)
+        if self.current_type_name.borrow().is_some() {
+            let registration = {
+                let current_type_name= self.current_type_name.borrow();
+                let type_name = current_type_name.as_ref().unwrap();
+                self
+                    .property_type_registry
+                    .get(type_name)
+                    .ok_or_else(|| {
+                        de::Error::custom(format!(
+                            "TypeRegistration is missing for {}",
+                            type_name
+                        ))
+                    })?
+            };
+            let mut erased = erased_serde::Deserializer::erase(deserializer);
+            let res = (registration.deserialize)(&mut erased)
+                .map_err(<<D as serde::Deserializer<'de>>::Error as serde::de::Error>::custom);
+            res
+        }  else {
+            deserializer.deserialize_any(AnyPropVisiter {
+                property_type_registry: self.property_type_registry,
+                current_type_name: self.current_type_name,
+            })
+        }
     }
 }
 
-struct AnyPropVisiter;
+struct AnyPropVisiter<'a> {
+    property_type_registry: &'a PropertyTypeRegistry,
+    current_type_name: Rc<RefCell<Option<String>>>,
+}
 
-impl<'de> Visitor<'de> for AnyPropVisiter {
+impl<'a, 'de> Visitor<'de> for AnyPropVisiter<'a> {
     type Value = Box<dyn Property>;
     fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
         formatter.write_str("property value")
@@ -251,7 +299,10 @@ impl<'de> Visitor<'de> for AnyPropVisiter {
     {
         let mut dynamic_properties = DynamicProperties::default();
         while let Some(key) = map.next_key()? {
-            let prop = map.next_value::<Box<dyn Property>>()?;
+            let prop = map.next_value_seed(MapValueDeserializer {
+                property_type_registry: self.property_type_registry,
+                current_type_name: self.current_type_name.clone(),
+            })?;
             if key == "type" {
                 dynamic_properties.type_name = prop
                     .val::<String>()
@@ -261,10 +312,27 @@ impl<'de> Visitor<'de> for AnyPropVisiter {
                 dynamic_properties.set_box(key, prop);
             }
         }
+
         Ok(Box::new(dynamic_properties))
     }
 }
 
+struct PropertyTypeDeserializer<'a> {
+    registration: &'a PropertyTypeRegistration,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for PropertyTypeDeserializer<'a> {
+    type Value = Box<dyn Property>;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let mut erased = erased_serde::Deserializer::erase(deserializer);
+        (self.registration.deserialize)(&mut erased)
+            .map_err(<<D as serde::Deserializer<'de>>::Error as serde::de::Error>::custom)
+    }
+}
+
 impl Property for DynamicProperties {
     #[inline]
     fn any(&self) -> &dyn Any {

crates/bevy_property/src/lib.rs

@@ -3,10 +3,13 @@
 mod property;
 mod properties;
 mod dynamic_properties;
+mod type_registry;
+pub mod ron;
 
 pub use property::*;
 pub use properties::*;
 pub use dynamic_properties::*;
+pub use type_registry::*;
 
 pub use bevy_property_derive::*; 
 pub use serde;

crates/bevy_property/src/ron.rs

@@ -0,0 +1,19 @@
+use ron::de::Deserializer;
+use std::{cell::RefCell, rc::Rc};
+use crate::{DynamicPropertiesDeserializer, PropertyTypeRegistry, DynamicProperties};
+use serde::de::DeserializeSeed;
+
+pub fn deserialize_dynamic_properties(ron_string: &str, property_type_registry: &PropertyTypeRegistry) -> Result<DynamicProperties, ron::Error> {
+    let mut deserializer = Deserializer::from_str(&ron_string).unwrap();
+    let last_type_name = Rc::new(RefCell::new(None));
+    let mut callback = |ident: &Option<&[u8]>| {
+        let mut last_type_name = last_type_name.borrow_mut();
+        *last_type_name = ident.map(|i| String::from_utf8(i.to_vec()).unwrap());
+    };
+    deserializer.set_callback(&mut callback);
+    let dynamic_properties_deserializer = DynamicPropertiesDeserializer {
+        current_type_name: last_type_name.clone(),
+        property_type_registry: &property_type_registry,
+    };
+    dynamic_properties_deserializer.deserialize(&mut deserializer)
+}

crates/bevy_property/src/type_registry.rs

@@ -0,0 +1,43 @@
+use crate::Property;
+use serde::Deserialize;
+use std::{any::TypeId, collections::HashMap};
+
+#[derive(Default)]
+pub struct PropertyTypeRegistry {
+    pub registrations: HashMap<String, PropertyTypeRegistration>,
+}
+
+impl PropertyTypeRegistry {
+    pub fn register<T>(&mut self)
+    where
+        T: Property + for<'de> Deserialize<'de>,
+    {
+        let registration = PropertyTypeRegistration::of::<T>();
+        self.registrations.insert(registration.short_name.to_string(), registration);
+    }
+
+    pub fn get(&self, type_name: &str) -> Option<&PropertyTypeRegistration> {
+        self.registrations.get(type_name)
+    }
+}
+
+#[derive(Clone)]
+pub struct PropertyTypeRegistration {
+    pub ty: TypeId,
+    pub deserialize: fn(deserializer: &mut dyn erased_serde::Deserializer) -> Result<Box<dyn Property>, erased_serde::Error>,
+    pub short_name: &'static str,
+}
+
+impl PropertyTypeRegistration {
+    pub fn of<T: Property + for<'de> Deserialize<'de>>() -> Self {
+        let ty = TypeId::of::<T>();
+        Self {
+            ty,
+            deserialize: |deserializer: &mut dyn erased_serde::Deserializer| {
+                let property = <T as Deserialize>::deserialize(deserializer)?;
+                Ok(Box::new(property))
+            },
+            short_name: std::any::type_name::<T>().split("::").last().unwrap(),
+        }
+    }
+}

crates/bevy_scene/src/component_registry.rs

@@ -1,14 +1,20 @@
 use bevy_app::AppBuilder;
-use bevy_property::{Properties, Property};
+use bevy_property::{Properties, Property, PropertyTypeRegistry};
 use legion::{
     prelude::{Entity, World},
-    storage::{Component, ComponentTypeId, ComponentResourceSet},
+    storage::{Component, ComponentResourceSet, ComponentTypeId},
 };
+use serde::Deserialize;
 use std::{
     collections::HashMap,
     sync::{Arc, RwLock},
 };
 
+#[derive(Clone, Default)]
+pub struct PropertyTypeRegistryContext {
+    pub value: Arc<RwLock<PropertyTypeRegistry>>,
+}
+
 #[derive(Default)]
 pub struct ComponentRegistryContext {
     pub value: Arc<RwLock<ComponentRegistry>>,
@@ -69,9 +75,10 @@ impl ComponentRegistration {
                 component.apply(property);
                 world.add_component(entity, component).unwrap();
             },
-            component_properties_fn: |component_resource_set: &ComponentResourceSet, index: usize| {
+            component_properties_fn: |component_resource_set: &ComponentResourceSet,
+                                      index: usize| {
                 // the type has been looked up by the caller, so this is safe
-               unsafe { &component_resource_set.data_slice::<T>()[index] }
+                unsafe { &component_resource_set.data_slice::<T>()[index] }
             },
             short_name: ty.0.split("::").last().unwrap(),
         }
@@ -82,6 +89,9 @@ pub trait RegisterComponent {
     fn register_component<T>(&mut self) -> &mut Self
     where
         T: Properties + Component + Default;
+    fn register_property_type<T>(&mut self) -> &mut Self
+    where
+        T: Property + for<'de> Deserialize<'de>;
 }
 
 impl RegisterComponent for AppBuilder {
@@ -98,4 +108,18 @@ impl RegisterComponent for AppBuilder {
         }
         self
     }
+
+    fn register_property_type<T>(&mut self) -> &mut Self
+    where
+        T: Property + for<'de> Deserialize<'de>,
+    {
+        {
+            let registry_context = self
+                .resources()
+                .get_mut::<PropertyTypeRegistryContext>()
+                .unwrap();
+            registry_context.value.write().unwrap().register::<T>();
+        }
+        self
+    }
 }

crates/bevy_scene/src/lib.rs

@@ -11,7 +11,8 @@ pub struct ComponentRegistryPlugin;
 
 impl AppPlugin for ComponentRegistryPlugin {
     fn build(&self, app: &mut AppBuilder) {
-        app.init_resource::<ComponentRegistryContext>();
+        app.init_resource::<ComponentRegistryContext>()
+            .init_resource::<PropertyTypeRegistryContext>();
     }
 }
 

crates/bevy_scene/src/scene.rs

@@ -1,17 +1,28 @@
-use crate::ComponentRegistry;
+use crate::{ComponentRegistry, PropertyTypeRegistryContext};
 use anyhow::Result;
+use bevy_app::FromResources;
 use bevy_asset::AssetLoader;
-use bevy_property::DynamicProperties;
-use legion::prelude::{Entity, World};
-use serde::{Deserialize, Serialize};
-use std::{num::Wrapping, path::Path};
+use bevy_property::{DynamicProperties, PropertyTypeRegistry, DynamicPropertiesDeserializer};
+use legion::prelude::{Entity, Resources, World};
+use serde::{
+    de::{DeserializeSeed, SeqAccess, Visitor, MapAccess, Error},
+    Serialize,
+    Deserialize
+};
+use std::{cell::RefCell, num::Wrapping, path::Path, rc::Rc};
 use thiserror::Error;
 
-#[derive(Serialize, Deserialize, Default)]
+#[derive(Default)]
 pub struct Scene {
     pub entities: Vec<SceneEntity>,
 }
 
+#[derive(Serialize)]
+pub struct SceneEntity {
+    pub entity: u32,
+    pub components: Vec<DynamicProperties>,
+}
+
 #[derive(Error, Debug)]
 pub enum SceneAddError {
     #[error("Scene contains an unregistered component.")]
@@ -85,20 +96,219 @@ impl Scene {
     }
 }
 
-#[derive(Serialize, Deserialize)]
-pub struct SceneEntity {
-    pub entity: u32,
-    pub components: Vec<DynamicProperties>,
+impl Serialize for Scene {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.entities.serialize(serializer)
+    }
 }
 
-#[derive(Default)]
-pub struct SceneLoader;
+pub struct SceneDeserializer<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for SceneDeserializer<'a> {
+    type Value = Scene;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let mut scene = Scene::default();
+        scene.entities = deserializer.deserialize_seq(SceneEntitySeqVisiter {
+            property_type_registry: self.property_type_registry,
+            current_type_name: self.current_type_name,
+        })?;
+
+        Ok(scene)
+    }
+}
+
+struct SceneEntitySeqVisiter<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> Visitor<'de> for SceneEntitySeqVisiter<'a> {
+    type Value = Vec<SceneEntity>;
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("list of entities")
+    }
+
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: SeqAccess<'de>,
+    {
+        let mut entities = Vec::new();
+        while let Some(entity) = seq.next_element_seed(SceneEntityDeserializer {
+            property_type_registry: self.property_type_registry,
+            current_type_name: self.current_type_name.clone(),
+        })? {
+            entities.push(entity);
+        }
+
+        Ok(entities)
+    }
+}
+
+pub struct SceneEntityDeserializer<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for SceneEntityDeserializer<'a> {
+    type Value = SceneEntity;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        deserializer.deserialize_struct("", &["entity", "components"], SceneEntityVisiter {
+            property_type_registry: self.property_type_registry,
+            current_type_name: self.current_type_name,
+        })
+    }
+}
+
+
+#[derive(Deserialize)]
+#[serde(field_identifier, rename_all = "lowercase")]
+enum EntityField {
+    Entity,
+    Components,
+}
+
+pub const ENTITY_FIELD_ENTITY: &str = "entity";
+pub const ENTITY_FIELD_COMPONENTS: &str = "components";
+
+struct SceneEntityVisiter<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> Visitor<'de> for SceneEntityVisiter<'a> {
+    type Value = SceneEntity;
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("entities")
+    }
+
+    fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
+    where A: MapAccess<'de> {
+        let mut entity = None;
+        let mut components = None;
+        while let Some(key) = map.next_key()? {
+            match key {
+                EntityField::Entity => {
+                    if entity.is_some() {
+                        return Err(Error::duplicate_field(ENTITY_FIELD_ENTITY));
+                    }
+                    entity = Some(map.next_value::<u32>()?);
+                }
+                EntityField::Components => {
+                    if components.is_some() {
+                        return Err(Error::duplicate_field(ENTITY_FIELD_COMPONENTS));
+                    }
+
+                    components = Some(map.next_value_seed(ComponentVecDeserializer {
+                        current_type_name: self.current_type_name.clone(), 
+                        property_type_registry: self.property_type_registry
+                    })?);
+                }
+            }
+        }
+
+        let entity = entity
+        .as_ref()
+        .ok_or_else(|| Error::missing_field(ENTITY_FIELD_ENTITY))?;
+
+        let components = components
+        .take()
+        .ok_or_else(|| Error::missing_field(ENTITY_FIELD_COMPONENTS))?;
+        Ok(SceneEntity {
+            entity: *entity,
+            components,
+        }) 
+    }
+}
+
+pub struct ComponentVecDeserializer<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> DeserializeSeed<'de> for ComponentVecDeserializer<'a> {
+    type Value = Vec<DynamicProperties>;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        deserializer.deserialize_seq(ComponentSeqVisiter {
+            property_type_registry: self.property_type_registry,
+            current_type_name: self.current_type_name,
+        })
+    }
+}
+
+
+struct ComponentSeqVisiter<'a> {
+    pub property_type_registry: &'a PropertyTypeRegistry,
+    pub current_type_name: Rc<RefCell<Option<String>>>,
+}
+
+impl<'a, 'de> Visitor<'de> for ComponentSeqVisiter<'a> {
+    type Value = Vec<DynamicProperties>;
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("list of components")
+    }
+
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: SeqAccess<'de>,
+    {
+        let mut dynamic_properties = Vec::new();
+        while let Some(entity) = seq.next_element_seed(DynamicPropertiesDeserializer {
+            current_type_name: self.current_type_name.clone(), 
+            property_type_registry: self.property_type_registry
+         })? {
+            dynamic_properties.push(entity);
+        }
+
+        Ok(dynamic_properties)
+    }
+}
+
+
+pub struct SceneLoader {
+    property_type_registry: PropertyTypeRegistryContext,
+}
+impl FromResources for SceneLoader {
+    fn from_resources(resources: &Resources) -> Self {
+        let property_type_registry = resources.get::<PropertyTypeRegistryContext>().unwrap();
+        SceneLoader {
+            property_type_registry: property_type_registry.clone(),
+        }
+    }
+}
 
 impl AssetLoader<Scene> for SceneLoader {
     fn from_bytes(&self, _asset_path: &Path, bytes: Vec<u8>) -> Result<Scene> {
+        let registry = self.property_type_registry.value.read().unwrap();
         let mut deserializer = ron::de::Deserializer::from_bytes(&bytes).unwrap();
-        let entities = Vec::<SceneEntity>::deserialize(&mut deserializer).unwrap();
-        Ok(Scene { entities })
+        let current_type_name = Rc::new(RefCell::new(None));
+        let scene_deserializer = SceneDeserializer {
+            property_type_registry: &registry,
+            current_type_name: current_type_name.clone(),
+        };
+        let mut callback = |ident: &Option<&[u8]>| {
+            let mut last_type_name = current_type_name.borrow_mut();
+            *last_type_name = ident.map(|i| String::from_utf8(i.to_vec()).unwrap());
+        };
+        deserializer.set_callback(&mut callback);
+
+
+        let scene = scene_deserializer.deserialize(&mut deserializer).unwrap();
+        Ok(scene)
     }
     fn extensions(&self) -> &[&str] {
         static EXTENSIONS: &[&str] = &["scn"];

crates/ron/src/de/mod.rs

@@ -23,6 +23,7 @@ mod value;
 /// you can use the `from_str` convenience function.
 pub struct Deserializer<'de> {
     bytes: Bytes<'de>,
+    type_callback: Option<&'de mut dyn FnMut(&Option<&[u8]>)>,
 }
 
 impl<'de> Deserializer<'de> {
@@ -35,12 +36,17 @@ impl<'de> Deserializer<'de> {
     pub fn from_bytes(input: &'de [u8]) -> Result<Self> {
         Ok(Deserializer {
             bytes: Bytes::new(input)?,
+            type_callback: None,
         })
     }
 
     pub fn remainder(&self) -> Cow<'_, str> {
         String::from_utf8_lossy(&self.bytes.bytes())
     }
+
+    pub fn set_callback(&mut self, callback: &'de mut dyn FnMut(&Option<&[u8]>)) {
+        self.type_callback = Some(callback);
+    }
 }
 
 /// A convenience function for reading data from a reader
@@ -578,12 +584,20 @@ impl<'de, 'a> de::MapAccess<'de> for CommaSeparated<'a, 'de> {
         K: DeserializeSeed<'de>,
     {
         if self.has_element()? {
-            if self.terminator == b')' {
+            let result = if self.terminator == b')' {
                 seed.deserialize(&mut IdDeserializer::new(&mut *self.de))
                     .map(Some)
             } else {
                 seed.deserialize(&mut *self.de).map(Some)
+            };
+            if let Some(ref mut callback) = self.de.type_callback {
+                let mut fast_forward_bytes = self.de.bytes.clone();
+                fast_forward_bytes.skip_ws()?;
+                fast_forward_bytes.consume(":");
+                fast_forward_bytes.skip_ws()?;
+                callback(&fast_forward_bytes.identifier().ok());
             }
+            result
         } else {
             Ok(None)
         }

crates/ron/src/parse.rs

@@ -315,7 +315,7 @@ impl<'a> Bytes<'a> {
         self.test_for(ident) && !self.check_ident_char(ident.len())
     }
 
-    fn check_ident_char(&self, index: usize) -> bool {
+    pub fn check_ident_char(&self, index: usize) -> bool {
         self.bytes
             .get(index)
             .map_or(false, |b| IDENT_CHAR.contains(b))

examples/scene/load_scene.rs

@@ -69,5 +69,4 @@ fn serialize_scene(world: &mut World, resources: &mut Resources) {
     let pretty_config = ron::ser::PrettyConfig::default().with_decimal_floats(true);
     let ron_string = ron::ser::to_string_pretty(&scene, pretty_config).unwrap();
     println!("{}", ron_string);
-    
 }

examples/scene/properties.rs

@@ -1,8 +1,13 @@
 use bevy::prelude::*;
+use bevy_property::ron::deserialize_dynamic_properties;
+use bevy_scene::PropertyTypeRegistryContext;
+use serde::{Deserialize, Serialize};
 
 fn main() {
     App::build()
         .add_default_plugins()
+        // If you need to deserialize custom property types, register them like this:
+        .register_property_type::<CustomProperty>()
         .add_startup_system(setup.system())
         .run();
 }
@@ -10,6 +15,7 @@ fn main() {
 #[derive(Properties, Default)]
 pub struct Test {
     a: usize,
+    hi: CustomProperty,
     nested: Nested,
 }
 
@@ -18,9 +24,15 @@ pub struct Nested {
     b: usize,
 }
 
-fn setup() {
+#[derive(Serialize, Deserialize, Default, Clone)]
+pub struct CustomProperty {
+    a: usize,
+}
+
+fn setup(property_type_registry: Res<PropertyTypeRegistryContext>) {
     let mut test = Test {
         a: 1,
+        hi: CustomProperty { a: 10 },
         nested: Nested { b: 8 },
     };
 
@@ -43,17 +55,31 @@ fn setup() {
     assert_eq!(test.a, 4);
 
     // Properties implement the serde Serialize trait. You don't need to derive it yourself!
-    let pretty_config = ron::ser::PrettyConfig::default().with_decimal_floats(true);
 
-    let ron_string = ron::ser::to_string_pretty(&test, pretty_config.clone()).unwrap();
+    let ron_string = serialize_ron(&test).unwrap();
     println!("{}\n", ron_string);
 
     // Dynamic properties can be deserialized
-    let dynamic_properties = ron::from_str::<DynamicProperties>(&ron_string).unwrap();
-    let round_tripped = ron::ser::to_string_pretty(&dynamic_properties, pretty_config).unwrap();
+    let dynamic_properties =
+        deserialize_dynamic_properties(&ron_string, &property_type_registry.value.read().unwrap())
+            .unwrap();
+
+    let round_tripped = serialize_ron(&dynamic_properties).unwrap();
     println!("{}", round_tripped);
     assert_eq!(ron_string, round_tripped);
 
     // This means you can patch Properties with dynamic properties deserialized from a string
     test.apply(&dynamic_properties);
 }
+
+fn serialize_ron<T>(properties: &T) -> Result<String, ron::Error>
+where
+    T: Serialize,
+{
+    let pretty_config = ron::ser::PrettyConfig::default().with_decimal_floats(true);
+    let mut buf = Vec::new();
+    let mut serializer = ron::ser::Serializer::new(&mut buf, Some(pretty_config), true)?;
+    properties.serialize(&mut serializer)?;
+    let ron_string = String::from_utf8(buf).unwrap();
+    Ok(ron_string)
+}