Ken Youens-Clark - Systems Programming with Rust: A Project-Based Primer

Rust is a programming language created by Graydon Hoare while working at Mozilla Research.He first started working on it around 2006 as a personal project, and by 2010 Mozilla had sponsored and announced the project.While the language is relatively new, it has quickly earned a passionate following of programmers who claim to even love using it.

Figure P-1. Here is a logo I made from an old Rush logo. Being a kid playing the drums in the 1980s, you better believe I listened to a lot of Rush. Anyway, Rust is cool, and this logo proves it.

Often Rust is described as a systems programming language that has been designed for performance and safety.It has a syntax that resembles the C language, so youll find things like for loops, semicolon-terminated statements, and curly braces denoting block structures.

Rust is also a statically typed language, meaning that a variable can never change its type, like from a number to a string.If youre coming from languages like C/C++ or Java, this will be familiar because those languages are also statically typed.You dont always have to declare a variables type in Rust because the compiler can often figure it out from the context, but the variable is still never allowed to change its type.

If, like me, you are coming from a dynamically typed language like Perl, JavaScript, or Python, this could feel rather new.In those languages, a variable can change its type at any point in the program, like from a string to a file handle.The language may also silently treat a variable of one type like another; for instance, both Perl and Python will evaluate strings, numbers, lists, dictionaries, and more in a Boolean context which can lead to some surprising results.Interestingly, several dynamically typed languages including Python, Perl 6/Raku, and Julia have introduced type hints or gradual typing systems where a variable can be basically untyped (Any) or some specific type like an integer or string.

Although Rust bears a strong resemblance to imperative, C-style languages, it has borrowed many exciting concepts from other languages and programming paradigms.Rust is not an object-oriented (OO) language like Java as there are no classes or inheritance in Rust.Instead Rust uses a struct (structure) to represent complex data types and traits to describe how types can behave.These structures can have methods, can mutate the internal state of the data, and might even be called objects in the documentation, but they are not objects in the formal sense of the word.

Rust has borrowed many exciting ideas from purely functional languages like Haskell.For instance, variables are immutable by default, meaning they cant be changed.Like many languages, functions are first-class values, which means they can be passed as arguments.Most exciting to my mind is Rusts use of enumerated and sum types, also called algebraic data types (ADTs), which allow you to represent, for instance, that a function can return a Result which can be either an Ok containing some value or an Err containing some other kind of value.Any code that deals with these values must handle all possibilities, so youre never at risk of forgetting to handle an error that could unexpectedly crash your program.