Summary

Rust uses a lot of special symbols like { and )

Many of these symbols come in pairs

These pairs of symbols need to nest inside each other

It’s good practice to follow layout rules to make your code easier to read

The rustfmt tool can help you get the layout right

You can use // or /* */ to add comments to your code

An expression is evaluated to a value of a specific type

Most of our Rust code is writing expressions

You can draw out expressions as trees, and then evaluate from the bottom up

Variables are a convenient way to capture expression results and give them useful names

Some expressions cause effects to happen

All expressions produce a result

But when an expression has nothing useful to produce, it produces (), aka unit

The body of a function is a block

Blocks can contain multiple statements, and end with an optional expression

The semicolon throws away the result of an expression

If you end your block with an expression without a semicolon, it will produce that value, otherwise it produces unit