Why would you prefer to use an empty struct{} ?

Using an empty struct (struct{}) in programming, particularly in languages like Go, offers several advantages primarily due to its memory efficiency and versatility in various programming patterns. Here are the key reasons why one might prefer to use an empty struct:

1. Zero Memory Allocation: An empty struct does not allocate memory. This is because it does not contain any data. In Go, the size of an empty struct is zero bytes[1][2]. This makes it extremely efficient, especially in scenarios where you need to create a large number of instances or use it in data structures.

2. Use in Data Structures: Empty structs are particularly useful in data structures where the presence of an element is more important than the element itself. For example, when implementing sets in Go, using map[T]struct{} is a common idiom. This utilizes the keys of the map to store the elements of the set and the zero-sized struct{} as a placeholder value to indicate the presence of the key. This approach is memory-efficient compared to using a map[T]bool where each boolean value would occupy more memory[1][11].

3. Signal or Marker: Empty structs can serve as signals or markers in code. They can be used to implement semaphore-like synchronization features or as markers in tagged unions and other similar constructs without adding overhead to the runtime memory usage[1].

4. Interface Implementation: They can be used to implement interfaces that do not require the struct to hold any data. This can be useful in various design patterns, such as strategy patterns or dependency injection, where the behavior is important but the state is not[1].

5. Compiler Optimizations: Languages like Go are designed to optimize the usage of empty structs, allowing for more efficient code compilation and execution[1][2].

6. Readability and Expressiveness: Us...