add FunctionLoader and StaticFunctionSearcher

an alternative to boxing closures

tests/tests.rs

@@ -160,6 +160,14 @@ fn module_reloading_works() {
     assert_eq!("hello lume", hello);
 }
 
+fn read_lume_to_string() -> String {
+    r#"return "hello lume""#.to_string()
+}
+
+fn read_lume_to_str() -> &'static str {
+    r#"return "hello lume""#
+}
+
 #[test]
 fn add_closure_searcher_works() {
     let lua = Lua::new();
@@ -288,10 +296,107 @@ impl UserData for Instrument {
     }
 }
 
-fn read_lume_to_string() -> String {
-    r#"return "hello lume""#.to_string()
+#[test]
+fn add_function_searcher_works() {
+    let lua = Lua::new();
+
+    let mut modules: HashMap<
+        String,
+        for<'ctx> fn(Context<'ctx>, Table<'ctx>, &str) -> rlua::Result<Function<'ctx>>,
+    > = HashMap::new();
+
+    modules.insert("cartridge".to_string(), cartridge_loader);
+
+    let title = lua
+        .context::<_, Result<String>>(|lua_ctx| {
+            lua_ctx.add_function_searcher(modules)?;
+
+            // Ensure global variable `cartridge` is unset.
+            let nil: String = lua_ctx.load("return type(cartridge)").eval()?;
+            assert_eq!(nil, "nil");
+
+            Ok(lua_ctx
+                .load(
+                    r#"local cartridge = require("cartridge")
+                       local smash = cartridge.pick()
+                       return smash:play()"#,
+                )
+                .eval()?)
+        })
+        .unwrap();
+
+    assert_eq!(title, "Super Smash Brothers 64");
 }
 
-fn read_lume_to_str() -> &'static str {
-    r#"return "hello lume""#
+#[test]
+fn add_static_function_searcher_works() {
+    let lua = Lua::new();
+
+    let mut modules: HashMap<
+        &'static str,
+        for<'ctx> fn(Context<'ctx>, Table<'ctx>, &str) -> rlua::Result<Function<'ctx>>,
+    > = HashMap::new();
+
+    modules.insert("cartridge", cartridge_loader);
+
+    let title = lua
+        .context::<_, Result<String>>(|lua_ctx| {
+            lua_ctx.add_static_function_searcher(modules)?;
+
+            // Ensure global variable `cartridge` is unset.
+            let nil: String = lua_ctx.load("return type(cartridge)").eval()?;
+            assert_eq!(nil, "nil");
+
+            Ok(lua_ctx
+                .load(
+                    r#"local cartridge = require("cartridge")
+                       local smash = cartridge.pick()
+                       return smash:play()"#,
+                )
+                .eval()?)
+        })
+        .unwrap();
+
+    assert_eq!(title, "Super Smash Brothers 64");
+}
+
+struct Cartridge {
+    title: String,
+}
+
+impl Cartridge {
+    pub fn pick() -> Self {
+        let title = "Super Smash Brothers 64".to_string();
+        Self { title }
+    }
+
+    pub fn play(&self) -> String {
+        self.title.clone()
+    }
+}
+
+impl UserData for Cartridge {
+    fn add_methods<'lua, M>(methods: &mut M)
+    where
+        M: UserDataMethods<'lua, Self>,
+    {
+        methods.add_method("play", |_, cartridge, ()| Ok(cartridge.play()));
+    }
+}
+
+fn cartridge_loader<'ctx>(
+    lua_ctx: Context<'ctx>,
+    env: Table<'ctx>,
+    name: &str,
+) -> rlua::Result<Function<'ctx>> {
+    let globals = lua_ctx.globals();
+    let pick = lua_ctx.create_function(|_, ()| Ok(Cartridge::pick()))?;
+    let tbl = lua_ctx.create_table()?;
+    tbl.set("pick", pick)?;
+    globals.set("cartridge", tbl)?;
+    Ok(lua_ctx
+        .load("return cartridge")
+        .set_name(name)?
+        .set_environment(env)?
+        .into_function()?)
 }