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mirror of https://github.com/google/comprehensive-rust.git synced 2024-12-17 23:23:43 +02:00
comprehensive-rust/src/hello-world.md
Martin Geisler d5359fa92a Add support for speaker notes
This implements a system for speaker notes via `details` elements and
some JavaScript. The general idea is

1. You add speaker notes to each page by wrapping some Markdown code
   in `<details> … </details>`. This is a standard HTML element for,
   well extra details. Browsers will render the element with a toggle
   control for showing/hiding the content.

2. We inject JavaScript on every page which finds these speaker note
   elements. They’re styled slightly and we keep their open/closed
   state in a browser local storage. This ensures that you can keep
   them open/closed across page loads.

3. We add a link to the speaker notes which will open in a new tab.
   The URL is amended with `#speaker-notes-open`, which we detect in
   the new tab: we hide the other content in this case.
   Simultaneously, we hide the speaker notes in the original window.

4. When navigating to a new page, we signal this to the other window.
   We then navigate to the same page. The logic above kicks in and
   hides the right part of the content. This lets the users page
   through the course using either the regular window or the speaker
   notes — the result is the same and both windows stay in sync.

Tested in both Chrome and Firefox. When using a popup speaker note
window, the content loads more smoothly in Chrome, but it still works
fine in Firefox.

Fixes #53.
2023-01-05 07:46:18 +01:00

1.0 KiB

Hello World!

Let us jump into the simplest possible Rust program, a classic Hello World program:

fn main() {
    println!("Hello 🌍!");
}

What you see:

  • Functions are introduced with fn.
  • Blocks are delimited by curly braces like in C and C++.
  • The main function is the entry point of the program.
  • Rust has hygienic macros, println! is an example of this.
  • Rust strings are UTF-8 encoded and can contain any Unicode character.

This slide tries to make the students comfortable with Rust code. They will see a ton of it over the next four days so we start small with something familiar.

Key points:

  • Rust is very much like other languages in the C/C++/Java tradition. It is imperative (not functional) and it doesn't try to reinvent things unless absolutely necessary.

  • Rust is modern with full support for things like Unicode.

  • Rust uses macros for situations where you want to have a variable number of arguments (no function overloading).