Mastering Unit Structs in Rust

Rust's struct types are fundamental for organizing data. While most structs hold fields, Rust also offers a special type of struct: the unit struct. Unit structs are valuable for signaling intent or implementing traits without carrying any data. This challenge will help you understand and utilize them effectively.

Problem Description

Your task is to define and use a unit struct in Rust. You will create a unit struct that represents a "NoOperation" command or event. This struct will be used in a scenario where different actions can be performed, and sometimes, no action is required.

Key Requirements:

1. Define a unit struct named NoOperation.
2. This struct should not contain any fields.
3. Create a function that accepts a generic type and, if it's of type NoOperation, prints a specific message. Otherwise, it should print a different message indicating a valid operation.

Expected Behavior:

When the function is called with an instance of NoOperation, it should output: "Performing no operation." When the function is called with any other valid value (e.g., a number, a string, or another struct), it should output: "Performing a valid operation."

Examples

Example 1:

Input:

let op: NoOperation = NoOperation;
perform_action(op);

Output:

Performing no operation.

Explanation: The perform_action function receives an instance of NoOperation and correctly identifies it, printing the designated message.

Example 2:

Input:

let action = 42;
perform_action(action);

Output:

Performing a valid operation.

Explanation: The perform_action function receives an integer and, since it's not NoOperation, prints the general operation message.

Example 3:

Input:

let command = "Execute";
perform_action(command);

Output:

Performing a valid operation.

Explanation: The perform_action function receives a string slice and, not being NoOperation, prints the general operation message.

Constraints

• The NoOperation struct must be a unit struct (no fields).
• The perform_action function should be generic to accept any type.
• The output messages must exactly match those specified in the "Expected Behavior" section.

Notes

• Recall how to define unit structs in Rust.
• Consider using pattern matching or std::mem::discriminant for type comparison within the generic function, though a simpler approach might suffice for this specific problem.
• Think about how to instantiate a unit struct.