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#![forbid(unsafe_code)] //! An easily reusable game bot for deterministic games. //! //! It is required to implement the trait [`Game`][game] for your game to use this crate. //! //! # Examples //! //! A game where you win by selecting `10`. //! //! ```rust //! use std::ops::RangeInclusive; //! //! #[derive(Clone)] //! struct ChooseTen; //! //! impl rubot::Game for ChooseTen { //! /// there is only one player, you! //! type Player = (); //! type Action = u8; //! /// did you choose a 10? //! type Fitness = bool; //! type Actions = RangeInclusive<u8>; //! //! fn actions(&self, _: Self::Player) -> (bool, Self::Actions) { //! (true, 1..=10) //! } //! //! fn execute(&mut self, action: &u8, _: Self::Player) -> Self::Fitness { //! *action == 10 //! } //! } //! //! fn main() { //! use rubot::Bot; //! use std::time::Duration; //! //! let mut bot = Bot::new(()); //! assert_eq!( //! bot.select(&ChooseTen, Duration::from_secs(1)), //! Some(10) //! ); //! } //! ``` //! //! Please visit the [examples folder][ex] or the [`trait Game`][game] documentation //! for more realistic examples. //! //! [ab]:alpha_beta/struct.Bot.html //! [ex]:https://github.com/lcnr/rubot/tree/master/examples //! [game]:trait.Game.html pub mod alpha_beta; pub mod tree; #[allow(unused)] #[doc(hidden)] pub mod brute; #[cfg(test)] mod tests; use std::cmp::PartialEq; use std::fmt::{self, Debug}; use std::ops::Drop; use std::time::{Duration, Instant}; /// An interface required to interact with [`GameBot`s][bot]. /// /// # Examples /// /// Implementing this trait for `21 flags`. The game has the following rules: /// /// - at the beginning there are 21 flags. /// - 2 players draw 1, 2 or 3 flags in alternating turns /// - the player who removes the last flag wins /// /// This example is really simplified and should be viewed as such. /// For more realistic examples visit the [`/examples`][examples] folder of this project. /// /// ```rust /// use std::{ /// ops::{Not, RangeInclusive}, /// time::Duration /// }; /// /// #[derive(Clone)] /// struct Game { /// flags: u32, /// active_player: Player /// } /// /// #[derive(Clone, Copy, PartialEq, Eq, Debug)] /// enum Player { /// A, /// B /// } /// /// impl Not for Player { /// type Output = Player; /// /// fn not(self) -> Player { /// match self { /// Player::A => Player::B, /// Player::B => Player::A, /// } /// } /// } /// /// impl Game { /// fn remove_flags(&mut self, flags: u32) { /// self.flags -= flags; /// self.active_player = !self.active_player; /// } /// /// fn winner(&self) -> Player { /// assert_eq!(self.flags, 0); /// !self.active_player /// } /// } /// /// impl rubot::Game for Game { /// type Player = Player; /// type Action = u32; /// /// `true` if the player wins the game, `false` otherwise. /// type Fitness = bool; /// type Actions = RangeInclusive<u32>; /// /// fn actions(&self, player: Self::Player) -> (bool, Self::Actions) { /// (player == self.active_player, 1..=std::cmp::min(self.flags, 3)) /// } /// /// fn execute(&mut self, action: &Self::Action, player: Self::Player) -> Self::Fitness { /// (action, player, &self); /// self.remove_flags(*action); /// self.flags == 0 && player == self.winner() /// } /// /// /// The fitness is only `true` if the game is won. /// fn is_upper_bound(&self, fitness: Self::Fitness, player: Self::Player) -> bool { /// fitness /// } /// } /// /// fn main() { /// use rubot::{Bot, ToCompletion}; /// let mut player_a = Bot::new(Player::A); /// let mut player_b = Bot::new(Player::B); /// let mut game = Game { flags: 21, active_player: Player::A }; /// loop { /// game.remove_flags(player_a.select(&game, ToCompletion).unwrap()); /// if game.flags == 0 { break } /// /// game.remove_flags(player_b.select(&game, ToCompletion).unwrap()); /// if game.flags == 0 { break } /// } /// // In case both players play perfectly, the player who begins should always win. /// assert_eq!(game.winner(), Player::A, "players are not playing optimally"); /// } /// ``` /// /// # Template /// /// A template which can be used to implement this trait more quickly. /// /// ```rust /// #[derive(Clone)] /// struct PlaceholderGame; /// #[derive(Clone, Copy)] /// struct PlaceholderPlayer; /// #[derive(Clone, PartialEq)] /// struct PlaceholderAction; /// #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq)] /// struct PlaceholderFitness; /// /// impl rubot::Game for PlaceholderGame { /// type Player = PlaceholderPlayer; /// type Action = PlaceholderAction; /// type Fitness = PlaceholderFitness; /// type Actions = Vec<Self::Action>; /// /// fn actions(&self, player: Self::Player) -> (bool, Self::Actions) { /// unimplemented!(); /// } /// /// fn execute(&mut self, action: &Self::Action, player: Self::Player) -> Self::Fitness { /// unimplemented!(); /// } /// } /// ``` /// [bot]: trait.GameBot.html /// [act]: trait.Game.html#associatedtype.Action /// [player]: trait.Game.html#associatedtype.player /// [examples]: https://github.com/lcnr/rubot/tree/master/examples pub trait Game: Clone { /// The player type. type Player: Copy; /// An executable action. type Action: PartialEq + Clone; /// The fitness of a state. type Fitness: Ord + Copy; /// The collection returned by [`actions`][ac]. /// /// [ac]:trait.Game.html#tymethod.actions type Actions: IntoIterator<Item = Self::Action>; /// Returns all currently possible actions and if they are executed by the given `player`. fn actions(&self, player: Self::Player) -> (bool, Self::Actions); /// Execute a given `action`, returning the new `fitness` for the given `player`. /// The returned fitness is always from the perspective of `player`, /// even if the `player` is not active. /// /// A correctly implemented `GameBot` will only call this function with /// actions generated by [`actions`][actions]. /// /// [actions]: trait.Game.html#tymethod.actions fn execute(&mut self, action: &Self::Action, player: Self::Player) -> Self::Fitness; /// Returns the fitness after `action` is executed. /// The returned fitness is always from the perspective of `player`, /// even if the `player` is not active. /// /// This function should always return the same [`Fitness`][fit] as calling [`execute`][exe]. /// /// ```rust /// # use rubot::Game; /// # #[derive(Clone)] /// # struct GameState; /// # impl rubot::Game for GameState { /// # type Player = (); /// # type Action = (); /// # type Fitness = bool; /// # type Actions = Option<()>; /// # /// # fn actions(&self, _player: Self::Player) -> (bool, Self::Actions) { /// # (true, Some(())) /// # } /// # /// # fn execute(&mut self, _action: &Self::Action, _player: Self::Player) -> Self::Fitness { /// # true /// # } /// # } /// # let player = (); /// # let action = (); /// let mut state = GameState; /// /// let look_ahead = state.look_ahead(&action, player); /// let execute = state.execute(&action, player); /// /// assert_eq!(look_ahead, execute); /// ``` /// [fit]: trait.Game.html#associatedtype.Fitness /// [exe]: trait.Game.html#tymethod.execute #[inline] fn look_ahead(&self, action: &Self::Action, player: Self::Player) -> Self::Fitness { self.clone().execute(action, player) } /// Returns `true` if the given `fitness` is one of the best currently possible outcomes for the given `player`. /// /// A good example is a checkmate in chess, as there does not exist a better game state than having won. #[inline] fn is_upper_bound(&self, fitness: Self::Fitness, player: Self::Player) -> bool { let _ = (fitness, player); false } /// Returns `true` if the given `fitness` is one of the worst currently possible outcomes for the given `player`. /// /// A good example is a checkmate in chess, as there does not exist a worse game state than having lost. #[inline] fn is_lower_bound(&self, fitness: Self::Fitness, player: Self::Player) -> bool { let _ = (fitness, player); false } } /// Converts a type into a [`RunCondition`][rc] used by [`Bot::select`][sel]. /// It is recommended to mostly use [`Duration`][dur]. /// /// # Examples /// /// ```rust /// # struct Game; /// # struct Bot; /// # impl Bot { /// # fn select<U: rubot::IntoRunCondition>(&mut self, state: &Game, condition: U) -> Option<()> { /// # Some(()) /// # } /// # } /// use std::time::Duration; /// /// let available_time = Duration::from_secs(2); /// /// let game: Game = // ... /// # Game; /// let mut bot: Bot = // ... /// # Bot; /// assert!(bot.select(&game, available_time).is_some()) /// ``` /// /// # Implementations /// /// - [`Duration`][dur]: `select` runs for the specified duration /// - [`ToCompletion`][complete]: `select` runs until it found the perfect action /// - [`Depth`][depth]: `select` analyses up the to given depth and returns to best action at that depth /// - [`Instant`][instant]: `select` runs until the given `Instant` is in the past /// - [`Logger`][logger]: takes another run condition and stores information about the last call to `select` /// /// [rc]: trait.RunCondition.html /// [dur]: https://doc.rust-lang.org/std/time/struct.Duration.html /// [complete]: struct.ToCompletion.html /// [depth]: struct.Depth.html /// [instant]: https://doc.rust-lang.org/std/time/struct.Instant.html /// [logger]: struct.Logger.html /// [sel]: alpha_beta/struct.Bot.html#method.select /// pub trait IntoRunCondition { type RunCondition: RunCondition; /// consumes `self` and returns a `RunCondition`. /// /// [rc]: trait.RunCondition.html fn into_run_condition(self) -> Self::RunCondition; } impl<T> IntoRunCondition for T where T: RunCondition, { type RunCondition = Self; fn into_run_condition(self) -> Self { self } } /// Can be converted into [`RunCondition`][rc] which returns `true` for the first `self.0` steps. /// This should only be used for debugging and testing as unlike `Duration`, `ToCompletion` or `Depth`, /// the total amount of steps needed is not directly indicative of search depth and can change between minor versions. /// /// [rc]: trait.RunCondition.html #[derive(Clone, Copy, Debug)] pub struct Steps(pub u32); /// The [`RunCondition`][rc] created by [`Steps`][steps]`::into_run_condition` /// /// [rc]: trait.RunCondition.html /// [steps]: struct.Steps.html #[doc(hidden)] #[derive(Debug)] pub struct InnerSteps(u32, u32); impl IntoRunCondition for Steps { type RunCondition = InnerSteps; fn into_run_condition(self) -> InnerSteps { InnerSteps(0, self.0) } } impl RunCondition for InnerSteps { #[inline] fn step(&mut self) -> bool { self.0 += 1; self.0 < self.1 } #[inline] fn depth(&mut self, _: u32) -> bool { true } } /// Creates a [`RunCondition`][rc] which returns `true` until this `Duration` has passed. /// /// [rc]: trait.RunCondition.html impl IntoRunCondition for Duration { type RunCondition = Instant; fn into_run_condition(self) -> Instant { Instant::now() + self } } /// A condition which indicates if [`Bot::select`][sel] should keep on running. /// It is recommended to use [`Duration`][dur] for nearly all use cases. /// /// A list of all already implemented `RunCondition`s can be found [here][into]. /// /// [sel]: alpha_beta/struct.Bot.html#method.select /// [dur]: https://doc.rust-lang.org/std/time/struct.Duration.html /// [into]: trait.IntoRunCondition.html#implementations-1 pub trait RunCondition { /// Called at each search step, instantly stops all calculations by returning `false`. fn step(&mut self) -> bool; /// Called after every finished search depth, instantly stops all calculations by returning `false`. fn depth(&mut self, depth: u32) -> bool; } /// Returns `true` while the `Instant` is still in the future impl RunCondition for Instant { #[inline] fn step(&mut self) -> bool { Instant::now() < *self } #[inline] fn depth(&mut self, _: u32) -> bool { Instant::now() < *self } } /// A struct implementing [`RunCondition`][rc] which always returns `true`. /// /// This means that the bot will always run until the best action was found. /// /// # Examples /// /// ```rust /// # use rubot::{Bot, tree::Node, ToCompletion}; /// let tree = Node::root().with_children(&[ /// Node::new(false, 7).with_children(&[ /// Node::new(true, 4), /// Node::new(true, 2), /// ]), /// Node::new(false, 5).with_children(&[ /// Node::new(true, 8), /// Node::new(true, 9) /// ]), /// ]); /// /// let mut bot = Bot::new(true); /// assert_eq!(bot.select(&tree, ToCompletion), Some(1)); /// ``` /// [rc]: trait.RunCondition.html #[derive(Clone, Copy, Debug)] pub struct ToCompletion; impl RunCondition for ToCompletion { #[inline] fn step(&mut self) -> bool { true } #[inline] fn depth(&mut self, _: u32) -> bool { true } } /// A struct implementing [`RunCondition`][rc] returning cancelling the computation once the depth `self.0` /// is reached. /// /// # Examples /// /// ```rust /// # use rubot::{Bot, tree::Node, Depth}; /// let tree = Node::root().with_children(&[ /// Node::new(false, 7).with_children(&[ /// Node::new(true, 4), /// Node::new(true, 2), /// ]), /// Node::new(false, 5).with_children(&[ /// Node::new(true, 8), /// Node::new(true, 9) /// ]), /// ]); /// /// let mut bot = Bot::new(true); /// assert_eq!(bot.select(&tree, Depth(0)), Some(0)); /// assert_eq!(bot.select(&tree, Depth(1)), Some(1)); /// ``` /// [rc]: trait.RunCondition.html #[derive(Clone, Copy, Debug)] pub struct Depth(pub u32); impl RunCondition for Depth { #[inline] fn step(&mut self) -> bool { true } #[inline] fn depth(&mut self, depth: u32) -> bool { self.0 > depth } } /// A struct implementing [`IntoRunCondition`] which can be used to log a call to [`select`][sel]. /// For more details you can visit the individual methods. /// /// # Examples /// /// ```rust /// # use rubot::{Bot, tree::Node, ToCompletion, Logger}; /// # use std::time::Duration; /// let tree = Node::root().with_children(&[ /// Node::new(false, 7).with_children(&[ /// Node::new(true, 4), /// Node::new(true, 2), /// ]), /// Node::new(false, 5).with_children(&[ /// Node::new(true, 8), /// Node::new(true, 9) /// ]), /// ]); /// /// let mut bot = Bot::new(true); /// let mut logger = Logger::new(ToCompletion); /// assert_eq!(bot.select(&tree, &mut logger), Some(1)); /// /// assert_eq!(logger.depth(), 2); /// // the total duration of `bot.select` /// assert!(logger.duration() < Duration::from_secs(1)); /// ``` /// [sel]: alpha_beta/struct.Bot.html#method.select pub struct Logger<T: IntoRunCondition> { condition: T::RunCondition, steps: u32, depth: u32, completed: bool, duration: Duration, } impl<T: IntoRunCondition> Debug for Logger<T> where T::RunCondition: Debug, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("Logger") .field("condition", &self.condition) .field("steps", &self.steps) .field("depth", &self.depth) .field("completed", &self.completed) .field("duration", &self.duration) .finish() } } impl<T: IntoRunCondition> Logger<T> { /// Creates a new `Logger` wrapping `condition`. pub fn new(condition: T) -> Self { Self { condition: condition.into_run_condition(), steps: 0, depth: 0, completed: true, duration: Duration::from_secs(0), } } /// Returns the total amount of times [`step`][step] was called during the last call to [`select`][sel]. /// /// [step]: trait.RunCondition.html#tymethod.step /// [sel]: alpha_beta/struct.Bot.html#method.select pub fn steps(&self) -> u32 { self.steps } /// Returns the deepest completed depth of the last call to [`select`][sel]. /// /// [sel]: alpha_beta/struct.Bot.html#method.select pub fn depth(&self) -> u32 { self.depth } /// Returns `true` if last call to [`select`][sel] was completed and `false` if it was /// cancelled by the run condition. /// /// [sel]: alpha_beta/struct.Bot.html#method.select pub fn completed(&self) -> bool { self.completed } /// Returns the total time spend during the last call to [`select`][sel]. /// /// [sel]: alpha_beta/struct.Bot.html#method.select pub fn duration(&self) -> Duration { self.duration } /// consumes `self` and returns the wrapped `condition` pub fn into_inner(self) -> T::RunCondition { self.condition } } /// The [`RunCondition`][rc] created by [`Logger`][logger]`::into_run_condition` /// /// [rc]: trait.RunCondition.html /// [logger]: struct.Logger.html #[doc(hidden)] pub struct InnerLogger<'a, T: IntoRunCondition>(&'a mut Logger<T>, Instant); impl<'a, T: IntoRunCondition> IntoRunCondition for &'a mut Logger<T> { type RunCondition = InnerLogger<'a, T>; fn into_run_condition(self) -> InnerLogger<'a, T> { self.steps = 0; self.depth = 0; InnerLogger(self, Instant::now()) } } impl<'a, T: IntoRunCondition> RunCondition for InnerLogger<'a, T> { #[inline] fn step(&mut self) -> bool { self.0.steps += 1; if self.0.condition.step() { true } else { self.0.completed = false; false } } #[inline] fn depth(&mut self, depth: u32) -> bool { self.0.depth = depth; if self.0.condition.depth(depth) { true } else { self.0.completed = false; false } } } impl<'a, T: IntoRunCondition> Drop for InnerLogger<'a, T> { fn drop(&mut self) { self.0.duration = self.1.elapsed(); } } pub use alpha_beta::Bot;