Rust Marker Traits: Identifying Data Shapes

Marker traits in Rust are zero-sized types that signal certain properties of a type without requiring any associated data. This challenge will guide you through creating and utilizing your own marker traits to categorize and differentiate data structures based on their intended use or behavior. Understanding marker traits is crucial for building more expressive and safe Rust code.

Problem Description

Your task is to design and implement two marker traits: Serializable and Validatable.

1. Serializable: This trait should indicate that a type can be serialized (e.g., converted into a string or byte representation) for storage or transmission.
2. Validatable: This trait should indicate that a type has a built-in validation mechanism.

You will then demonstrate their usage by creating concrete types that implement these traits and by writing a generic function that leverages these traits to process different data structures.

Key Requirements:

• Define two distinct marker traits: Serializable and Validatable.
• Implement these traits for at least three different struct types. One struct should implement only Serializable, another only Validatable, and a third should implement both.
• Write a generic function process_data that accepts any type T.
  • If T implements Serializable, the function should print a message indicating it's serializing the data.
  • If T implements Validatable, the function should print a message indicating it's validating the data.
  • The function should be able to handle types that implement neither, one, or both traits.

Expected Behavior:

When calling process_data with instances of your defined structs, the output should accurately reflect which traits are implemented.

Edge Cases:

• Consider how your process_data function behaves when given a type that implements neither trait.

Examples

Example 1:

Assume we have a User struct that is Serializable but not Validatable.

Input: An instance of User. Output:

Serializing data...

Explanation: Since User implements Serializable, the serialization message is printed. It does not implement Validatable, so no validation message is printed.

Example 2:

Assume we have a Config struct that is Validatable but not Serializable.

Input: An instance of Config. Output:

Validating data...

Explanation: Since Config implements Validatable, the validation message is printed. It does not implement Serializable, so no serialization message is printed.

Example 3:

Assume we have a Report struct that implements both Serializable and Validatable.

Input: An instance of Report. Output:

Serializing data...
Validating data...

Explanation: Since Report implements both traits, both the serialization and validation messages are printed.

Example 4:

Assume we have a LogEntry struct that implements neither trait.

Input: An instance of LogEntry. Output: (No output from process_data related to serialization or validation)

Explanation: LogEntry implements neither Serializable nor Validatable, so process_data does not trigger any trait-specific messages.

Constraints

• All code must be written in Rust.
• The solution should compile without errors or warnings.
• The process_data function must be generic and use trait bounds to check for trait implementations.

Notes

• Marker traits are defined simply by their name and the impl Trait for Type {} syntax. They do not require any methods.
• You can use if_chain (or similar conditional logic with trait checks) within your generic function to determine which traits are implemented. The std::any::Any trait is not to be used for this specific problem, as the goal is to create custom marker traits.
• Think about how you would structure your struct definitions and trait implementations to clearly demonstrate the concepts.