Programming Rust

Chapter 3. Basic Types

There are many, many types of books in the world, which makes good sense, because there are many, many types of people, and everybody wants to read something different.

Lemony Snicket

Rust’s types serve several goals:

Safety

By checking a program’s types, the Rust compiler rules out whole classes of common mistakes. By replacing null pointers and unchecked unions with type-safe alternatives, Rust is even able to eliminate errors that are common sources of crashes in other languages.

Efficiency

Programmers have fine-grained control over how Rust programs represent values in memory, and can choose types they know the processor will handle efficiently. Programs needn’t pay for generality or flexibility they don’t use.

Concision

Rust manages all of this without requiring too much guidance from the programmer in the form of types written out in the code. Rust programs are usually less cluttered with types than the analogous C++ program would be.

Rather than using an interpreter or a just-in-time compiler, Rust is designed to use ahead-of-time compilation: the translation of your entire program to machine code is completed before it ever begins execution. Rust’s types help an ahead-of-time compiler choose good machine-level representations for the values your program operates on: representations whose performance you can predict, and which give you full access to the machine’s capabilities.

Rust is a statically typed language: without actually running the ...