advent-of-code/source/year_2020/day_12/extra.rs

//! [`Action`] and [`Instruction`] code.

/// The list of actions the ship can take.
#[derive(Debug, Eq, PartialEq)]
pub enum Action {
  /// Move North by a given value.
  North,
  /// Move East by a given value.
  East,
  /// Move South by a given value.
  South,
  /// Move West by a given value.
  West,
  /// Turn left by a given number of degrees.
  Left,
  /// Turn right by a given number of degrees.
  Right,
  /// Move forward by a given value in the direction the ship is facing.
  Forward,
}

impl From<char> for Action {
  fn from(input: char) -> Self {
    match input {
      'N' => Self::North,
      'E' => Self::East,
      'S' => Self::South,
      'W' => Self::West,
      'L' => Self::Left,
      'R' => Self::Right,
      'F' => Self::Forward,
      _ => unreachable!("{input}"),
    }
  }
}

/// The combination of an [`Action`] and the value for it.
#[derive(Debug)]
pub struct Instruction {
  /// Which action to take.
  pub action: Action,
  /// The amount to use for that action.
  pub value: i32,
}

impl From<&str> for Instruction {
  fn from(input: &str) -> Self {
    let mut chars = input.chars();

    let action = chars.next().map(Into::into).unwrap();
    let value = chars.collect::<String>().parse().unwrap();

    Self { action, value }
  }
}