Attribute Macro implementation 

#[implementation]

Implements a helper function _to_mlua_methods for a Rust impl block, enabling automatic registration of its methods with mlua::UserData.

When applied to an impl block, this macro scans for functions and generates an implementation of a private helper function. This function is later invoked by the mlua_magic_macros::compile! macro.

Behavior

• Static Functions (e.g., fn new() -> Self) are registered as static functions on the userdata, accessible in Lua as MyType.new().
• Immutable Methods (e.g., fn my_method(&self)) are registered as immutable methods, accessible in Lua as my_instance:my_method().
• Mutable Methods (e.g., fn my_mut_method(&mut self)) are registered as mutable methods, accessible in Lua as my_instance:my_mut_method().

Usage

Apply the macro directly to the impl block for the type:

#[mlua_magic_macros::structure]
struct Player { hp: i32 }

#[mlua_magic_macros::implementation]
impl Player {
    pub fn new() -> Self { Self { hp: 100 } }
    pub fn is_alive(&self) -> bool { self.hp > 0 }
    pub fn take_damage(&mut self, amount: i32) { self.hp -= amount; }
}

// Later, compile userdata:
mlua_magic_macros::compile!(Player, fields, methods);

Lua scripts may then call these methods:

local p = Player.new()
p:take_damage(30)
print(p:is_alive())

This macro is designed to work together with:

• #[mlua_magic_macros::structure] — for fields
• #[mlua_magic_macros::enumeration] — for enum variants
• mlua_magic_macros::compile! — final hookup to mlua::UserData