Trait objects

Use trait objects (&dyn Fn()) when you need runtime polymorphism and don't mind the small performance cost of dynamic dispatch.

Generics

Use generics (F: Fn()) for better performance through static dispatch, but at the cost of potential code bloat due to monomorphization.

Use Box<dyn Fn()> when you need to own the function and have runtime polymorphism, but be aware of the heap allocation overhead.

Feature	Trait Objects (`&dyn Fn()`)	Generics (`F: Fn()`)	Smart Pointer (`Box<dyn Fn()>`)
Type	Trait Object	Generic	Smart Pointer
Runtime/Compile-time	Runtime	Compile-time	Runtime
Use Case	When you need runtime polymorphism	When you need better performance and can handle code bloat	When you need to own the function and have runtime polymorphism
Dispatch	⚠️ Dynamic Dispatch	✅ Static Dispatch	⚠️ Dynamic Dispatch
Performance	⚠️ Small performance cost due to dynamic dispatch	✅ Better performance due to static dispatch	⚠️ Small performance cost due to dynamic dispatch
Code Bloat	✅ No code bloat	⚠️ Potential code bloat due to monomorphization	✅ No code bloat
Ownership	❌ No ownership	❌ No ownership	✅ Ownership
Heap Allocation	✅ No heap allocation	✅ No heap allocation	❌ Heap allocation overhead
Flexibility	❌ Less flexible, requires `dyn` keyword	⚠️ More flexible, requires generic parameter	❌ Less flexible, requires `Box` and `dyn` keywords
Commonalities	⚠️ Provides runtime polymorphism	✅ Provides static dispatch	⚠️ Provides runtime polymorphism
	⚠️ Requires `dyn` keyword	⚠️ Requires generic parameter	⚠️ Requires `Box` and `dyn` keywords
Differences	❌ No ownership, no heap allocation	❌ No ownership, no heap allocation	✅ Ownership, heap allocation overhead
	⚠️ Small performance cost	✅ Better performance, potential code bloat	⚠️ Small performance cost, heap allocation overhead