The Rust Programming Language

An overview of bits, bytes and the sizes of numbers that can be represented in a typical programming language.

Some preliminaries before we get started. Here we discuss the application entrypoint — the main function; also we discuss functions in general and the println! macro.

Learn about boolean, integral, floating-point types and the char type.

A description of some of the Rust operators such as +, <=, && and so on.

A discussion of scopes and how variables in inner scopes can shadow outer variables.

Global values that are unlikely to change.

Learn about the distinction between the stack and the heap,

Learn about the if statement, including some unusual syntax. (And no, Rust does not have a ternary ?: operator.)

A look at conditional and unconditional loops.

for loops... also very unusual.

A look at match which lets you pick the right option based on matching input plus additional conditions. Very powerful!

A simple example using control flow constructs.

A very important topic! Structs let us keep related data together in a single object.

(Note: there is no concept of constructor in Rust.)

A traffic light can be red, green or blue. How to best represent this information in a program?

Here we talk about a very useful type called Option<T>, the None/Some(x) duality, and also discuss the if let and while let declarations.

Learn how to store multiple values of any type in a single data structure as well as how to go over those values.

A slice is a read-only view into an array or a vector.

Learn about tuples, their destructuring and indexing. (Yes, destructuring is a word.)

Now that we know more about various data structures, let's revisit the match keyword and discuss pattern matching, an extremely powerful technique.

Learn about generic structures.

A look at the key Rust collections.

A vector is like an array, but resizeable. Also behaves like a stack.

A key-value store that allows fast access and update/upsert operations.

A data structure that represents a mathematical set.

Strings are used to store text (i.e., sequences of characters). Learn about both str and String. Both are valid UTF-8 sequences of bytes.

Why does str exist? Because an ordinary slice of a String is effectively a slice of Vec<u8>, which is not very useful.

Learn about the format! macro.

A tiny game.

We've already met the function main, but now we discuss functions at large.

A struct can have not just fields but also its own functions!

How do you store a function in a variable? How do you pass a function to some other function? These concerns are addressed with closures (a.k.a. lambda functions).

Traits let you specify that a type must possess certain aspects.

Three forms of syntax for passing traits as parameters.

A look at the Into trait, which helps with automatic conversions.

A way of giving your structs destructors.

One of two possible forms of dispatch. Static dispatch is when the compiler knows exactly which realization of function to call.

What if the compiler doesn't know which trait implementation to call?

You cannot make vectors of different objects. But if you really need to, you can make a vector of enum cases or of pointers (&, Box, Rc, etc.)

Learn about ownership, move semantics and move-able types.

We finally get to look at explicit use of lifetime specifiers. Woo-hoo!

A look at how lifetimes are defined in implementations of structs.

In addition to ownership/borrowing, Rust also supports the notion of reference-counted variables. These are somewhat easier to share. The approach is similar to C++'s shared_ptr/unique_ptr.

A reference-counted variable (Rc) is safe to share around within a single thread. But what if we want to share it around in multiple threads? How can we ensure its pointer count is actually safe from concurrent modification? That's what the Arc class is for.

Arc protects the reference count, but it doesn't protect the variable itself, so concurrent modification of the variable will still be prohibited by the Rust compiler. How can we get concurrent code that mutates the variable to work? One option is to use a Mutex.

In Rust, circular references are difficult to get right.