feat(engine): add immutable try_get* fns to reflection

3 files changed, 72 insertions, 0 deletions

diff --git a/engine-macros/src/reflection/enum_impl.rs b/engine-macros/src/reflection/enum_impl.rs
index 37abc34..14d91a7 100644
--- a/engine-macros/src/reflection/enum_impl.rs
+++ b/engine-macros/src/reflection/enum_impl.rs
@@ -352,6 +352,29 @@ fn generate_variants<'a>(
 
                     Ok(())
                 },
+                try_get_field: |target, field_index| { {
+                    #![allow(unreachable_code)]
+
+                    use std::any::Any;
+                    use #engine_crate_path::reflection::GetError;
+
+                    let target = target
+                        .downcast_ref::<Self>()
+                        .ok_or(GetError::WrongTargetType)?;
+
+                    let #variant_pattern = target else {
+                        return Err(GetError::WrongTargetEnumVariant);
+                    };
+
+                    let field: &dyn Any = match field_index {
+                        #field_index_match_arms
+                        _ => {
+                            return Err(GetError::IndexOutOfBounds);
+                        }
+                    };
+
+                    Ok(field)
+                } },
                 try_get_field_mut: |target, field_index| { {
                     #![allow(unreachable_code)]
 
diff --git a/engine-macros/src/reflection/struct_impl.rs b/engine-macros/src/reflection/struct_impl.rs
index 1cd9fb8..0ba426d 100644
--- a/engine-macros/src/reflection/struct_impl.rs
+++ b/engine-macros/src/reflection/struct_impl.rs
@@ -142,6 +142,24 @@ fn gen_impl(
                                 #get_default_value_fn
                             },
                             cast_dyn_any: |ptr| ptr.cast::<Self>(),
+                            try_get_field: |target, field_index| { {
+                                #![allow(unreachable_code)]
+
+                                let target = target
+                                    .downcast_ref::<Self>()
+                                    .ok_or(GetError::WrongTargetType)?;
+
+                                let #struct_pattern = target;
+
+                                let field: &dyn Any = match field_index {
+                                    #field_index_match_arms
+                                    _ => {
+                                        return Err(GetError::IndexOutOfBounds);
+                                    }
+                                };
+
+                                Ok(field)
+                            } },
                             try_get_field_mut: |target, field_index| { {
                                 #![allow(unreachable_code)]
 
diff --git a/engine-reflection/src/lib.rs b/engine-reflection/src/lib.rs
index 4ef688c..d9e2c72 100644
--- a/engine-reflection/src/lib.rs
+++ b/engine-reflection/src/lib.rs
@@ -109,6 +109,8 @@ pub struct Struct
     pub fields: &'static [Field],
     pub get_default_value: fn() -> Option<DefaultValueFn>,
     pub cast_dyn_any: CastDynAnyFn,
+    pub try_get_field:
+        fn(target: &dyn Any, field_index: usize) -> Result<&dyn Any, GetError>,
     pub try_get_field_mut:
         fn(target: &mut dyn Any, field_index: usize) -> Result<&mut dyn Any, GetError>,
 }
@@ -171,6 +173,9 @@ pub struct EnumVariant
         fields: &mut dyn Iterator<Item = Box<dyn Any>>,
     ) -> Result<(), EnumVariantWriteNewToError>,
 
+    pub try_get_field:
+        fn(target: &dyn Any, field_index: usize) -> Result<&dyn Any, GetError>,
+
     pub try_get_field_mut:
         fn(target: &mut dyn Any, field_index: usize) -> Result<&mut dyn Any, GetError>,
 }
@@ -288,6 +293,7 @@ pub struct Array
     pub get_item_type_name: FnWithDebug<&'static str>,
     pub length: usize,
     pub cast_dyn_any: CastDynAnyFn,
+    pub try_get_item: fn(target: &dyn Any, index: usize) -> Result<&dyn Any, GetError>,
     pub try_get_item_mut:
         fn(target: &mut dyn Any, index: usize) -> Result<&mut dyn Any, GetError>,
 }
@@ -435,6 +441,15 @@ unsafe impl<T: Reflection, const LEN: usize> Reflection for [T; LEN]
         get_item_type_name: FnWithDebug::new(|| type_name::<T>()),
         length: LEN,
         cast_dyn_any: |ptr| ptr.cast::<Self>(),
+        try_get_item: |target, index| {
+            let target = target
+                .downcast_ref::<Self>()
+                .ok_or(GetError::WrongTargetType)?;
+
+            let item = target.get(index).ok_or(GetError::IndexOutOfBounds)?;
+
+            Ok(item)
+        },
         try_get_item_mut: |target, index| {
             let target = target
                 .downcast_mut::<Self>()
@@ -507,6 +522,21 @@ unsafe impl<T: Reflection> Reflection for Option<T>
 
                     Ok(())
                 },
+                try_get_field: |target, field_index| {
+                    if field_index != 0 {
+                        return Err(GetError::IndexOutOfBounds);
+                    }
+
+                    let target = target
+                        .downcast_ref::<Self>()
+                        .ok_or(GetError::WrongTargetType)?;
+
+                    let Some(value_field) = target else {
+                        return Err(GetError::WrongTargetEnumVariant);
+                    };
+
+                    Ok(value_field)
+                },
                 try_get_field_mut: |target, field_index| {
                     if field_index != 0 {
                         return Err(GetError::IndexOutOfBounds);
@@ -539,6 +569,7 @@ unsafe impl<T: Reflection> Reflection for Option<T>
 
                     Ok(())
                 },
+                try_get_field: |_, _| Err(GetError::IndexOutOfBounds),
                 try_get_field_mut: |_, _| Err(GetError::IndexOutOfBounds),
             },
         ],