Tuples, structs, and tuple structs are three alternatives in Rust for handling multiple values of different types. Tuples are anonymous types with anonymous fields, structs are named types with named fields, and tuple structs are in the middle of the spectrum, providing named types with anonymous fields.
The main differences between tuples and tuple structs are:
- Elements of a tuple struct are private by default and cannot be accessed outside the module they’re defined in.
- Tuple structs define a type, so two tuple structs with fields of the same type are two different types.
- Tuple structs can have attributes such as
#[must_use]or#[derive(...)]. - Tuple structs implement the
Fn*family by default, allowing them to be invoked like functions or passed in as parameters to higher-order functions. - Tuple structs support the struct update syntax, simplifying the way to create a new instance of a struct where most of the values are equal to another instance of the same struct.
Use cases for each alternative are:
- Tuples: when the name of the type carries semantic information, and having names would likely be overkilling.
- Structs: when there’s more than one field, and having names helps read the code.
- Tuple structs: when you want to use types to further enhance the clarity of your code, and having names is not necessary.
In conclusion, tuples, structs, and tuple structs can be used to fulfill more or less the same use cases, but the choice depends on how they impact the readability and maintainability of the code.