Can Go's `decorator()` function handle functions with specific return types without generics?

Passing Arbitrary Functions to Parameters in Go

In Go, passing functions as parameters allows for greater flexibility and code reuse. However, there are limitations when attempting to pass functions with different signatures as parameters.

Consider the scenario where you want to create a decorator() function capable of wrapping any existing function. For functions with a single parameter and return value (e.g., funcA), this is straightforward using func(interface{}) interface{} as the parameter type.

Question: Can a function like funcB, which accepts and returns specific types (in this case, string), be converted to a func(interface{}) interface{} type for compatibility with decorator()?

Answer: Unfortunately, this is not possible in Go without using generics. The reason lies in the fundamental differences in parameter passing mechanics between functions.

For instance, a function that accepts a struct as an argument receives each of its members individually. Conversely, a function accepting an interface{} containing that struct will receive two values: a descriptor for the struct's type and a pointer to the struct.

Therefore, to achieve the desired behavior, an adapter function would be required to bridge the gap between the original function's signature and the expected func(interface{}) interface{} type.

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