Add name expression BSN syntax (#38)

Co-authored-by: Carter Anderson <[email protected]>

Author: villor

crates/bevy_scene2/macros/src/bsn/codegen.rs

@@ -140,6 +140,15 @@ impl<const ALLOW_FLAT: bool> Bsn<ALLOW_FLAT> {
                         )
                     }
                 }
+                BsnEntry::NameExpression(expr_tokens) => {
+                    quote! {
+                        <#bevy_ecs::name::Name as PatchGetTemplate>::patch(
+                            move |value| {
+                                *value = Name({#expr_tokens}.into());
+                            }
+                        )
+                    }
+                }
             });
         }
 

crates/bevy_scene2/macros/src/bsn/parse.rs

@@ -73,7 +73,11 @@ impl Parse for BsnEntry {
             BsnEntry::InheritedScene(input.parse::<BsnInheritedScene>()?)
         } else if input.peek(Token![#]) {
             input.parse::<Token![#]>()?;
-            BsnEntry::Name(input.parse::<Ident>()?)
+            if input.peek(Brace) {
+                BsnEntry::NameExpression(braced_tokens(input)?)
+            } else {
+                BsnEntry::Name(input.parse::<Ident>()?)
+            }
         } else if input.peek(Brace) {
             BsnEntry::SceneExpression(braced_tokens(input)?)
         } else if input.peek(Bracket) {

crates/bevy_scene2/macros/src/bsn/types.rs

@@ -12,6 +12,7 @@ pub struct Bsn<const ALLOW_FLAT: bool> {
 #[derive(Debug)]
 pub enum BsnEntry {
     Name(Ident),
+    NameExpression(TokenStream),
     GetTemplatePatch(BsnType),
     TemplatePatch(BsnType),
     GetTemplateConstructor(BsnConstructor),