BSN4

use std::collections::{HashMap, HashSet};
use std::hash::Hash;

pub struct Collection<'a, T> {
    items: Vec<&'a T>,
}

impl<'a, T> Collection<'a, T> {
    pub fn new(items: &'a [T]) -> Self {
        Self {

BSN4

Async Rust Practical Patterns and Gotchas

Struct Patterns

// For shared state across tasks, these are your main tools:
struct MyService {
    // Immutable shared state
    config: Arc<Config>,
    // Mutable shared state

BSN4

Rust Borrowing and Ownership Rules

Struct Methods

Use &mut self when:

• Modifying struct fields (e.g., update_score, play_round)
• Maintaining state between calls

Use &self when:

• Only reading values (e.g., get_player_move, announce_winner)

BSN4

use std::sync::Arc;
use tokio::sync::{broadcast, Mutex};
use tokio::time::{sleep, Duration};

#[derive(Debug)]
struct SharedContext {
    counter: i32,
    last_updated_by: String,
}

BSN4

use std::sync::Arc;
use tokio::sync::Mutex;
use tokio::time::{sleep, Duration};

// Our shared context that will be accessed by all workers
#[derive(Debug)]
struct SharedContext {
    counter: i32,
    last_updated_by: String,
}

BSN4

use rand::Rng;
use std::io::{self, Write};

#[derive(Debug, Default)]
struct Score {
    player: u32,
    computer: u32,
}

#[derive(Debug, PartialEq, Clone, Copy)]

BSN4

use rand::Rng;
use std::io::{self, Write};

#[derive(Debug)]
struct Score {
    player: u32,
    computer: u32,
}

#[derive(Debug, PartialEq, Clone)]

BSN4

defmodule RPS do
  defmodule Score, do: defstruct player: 0, computer: 0
  
  defmodule Context do
    defstruct [
      score: %Score{},
      rounds_to_play: 3,
      valid_moves: [:rock, :paper, :scissors],
      win_conditions: %{rock: :scissors, paper: :rock, scissors: :paper},
      io: IO

BSN4

defmodule RPS do
  defmodule Score, do: defstruct player: 0, computer: 0

  def play do
    %Score{}
    |> Stream.iterate(&play_round/1)
    |> Enum.at(3)
    |> announce_winner()
    |> maybe_play_again()
  end

BSN4

People

:bowtie:	😄 :smile:	😆 :laughing:
😊 :blush:	😃 :smiley:	☺️ :relaxed:
😏 :smirk:	😍 :heart_eyes:	😘 :kissing_heart:
😚 :kissing_closed_eyes:	😳 :flushed:	😌 :relieved:
😆 :satisfied:	😁 :grin:	😉 :wink:
😜 :stuck_out_tongue_winking_eye:	😝 :stuck_out_tongue_closed_eyes:	😀 :grinning:
😗 :kissing:	😙 :kissing_smiling_eyes:	😛 :stuck_out_tongue: