refactor(exporters): single registry source of truth

crates/exporters/src/lib.rs

@@ -6,16 +6,21 @@ use lib::{BlockPalette, StructureExporter};
 pub use litematica::LitematicaExporter;
 pub use mcfunction::McFunctionExporter;
 
-pub fn available_names() -> &'static [&'static str] {
-    &["mcfunction", "litematica"]
+type ExporterFactory = fn(&BlockPalette) -> Box<dyn StructureExporter>;
+
+const REGISTRY: &[(&str, ExporterFactory)] = &[
+    ("mcfunction", |p| Box::new(McFunctionExporter::new(p))),
+    ("litematica", |p| Box::new(LitematicaExporter::new(p))),
+];
+
+pub fn available_names() -> Vec<&'static str> {
+    REGISTRY.iter().map(|(name, _)| *name).collect()
 }
 
 pub fn build(name: &str, palette: &BlockPalette) -> Option<Box<dyn StructureExporter>> {
-    match name {
-        "mcfunction" => Some(Box::new(McFunctionExporter::new(palette))),
-        "litematica" => Some(Box::new(LitematicaExporter::new(palette))),
-        _ => None,
-    }
+    REGISTRY.iter()
+        .find(|(n, _)| *n == name)
+        .map(|(_, factory)| factory(palette))
 }
 
 #[cfg(test)]