Summary

The main we’ve seen so far is one example of a function.

We can define multiple other functions.

We can call functions similar to how we call macros (for example, println!).

Functions may take parameters, which are passed in from the caller.

Function parameters can be used as variables inside the body of a function.

Functions may return results of different types.

By default, functions return the unit () type.

A function body is a block, and may end with an expression, which will be its result value.

Function parameters are scoped to the function body.

Blocks create scopes for variables defined inside of them.

main is a normal function, but has some special rules:

• It cannot take any parameters.

• It can only have some special result types.