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ratsnake is an implementation of the video game Snake in Rust built using the Ratatui library. Guide the snake around the level to eat fruits, making it grow longer, but don't run into yourself!

Installation

In order to install ratsnake, you first need to have Rust and Cargo installed. You can then build the latest release of ratsnake and install it in ~/.cargo/bin by running:

cargo install ratsnake

Usage

ratsnake [<options>]

Run ratsnake to bring up the program's main menu.

ratsnake is optimized for display on 80 column by 24 line terminals. If your terminal is bigger than this, the interface will be centered in the middle. If your terminal is smaller, you're going to have a bad time.

All screens in ratsnake support directional movement with the arrow keys, h/j/k/l, w/a/s/d, and 2/4/6/8. In addition, pressing Ctrl+C at any point during program execution will immediately end the program.

Options

• -c <file>, --config <file> — Read program confguration from <file>. See "Configuration" below for more information.

• -h, --help — Show command-line usage

• -V, --version — Show current program version

Main Menu

The main menu allows the user to configure various options for Snake before starting a game. The options are saved to a file (See "Configuration" below) that is loaded on program startup and updated before starting a new game.

The following options can be set:

• Wraparound — If this option is set, the borders of the game level will wrap around so that the snake can pass into one side and come out the opposite. When this is not set, the snake will die upon coming into contact with a level border.

• Obstacles — If this option is set, random obstacles will be placed in the game level; coming into contact with one kills the snake.

• Fruits — Set the number of fruits present at all times. May be any integer from 1 through 10.

• Level Size — Set the dimensions of the game level, choosing from small (38×8), medium (53×12), and large (76×19).

Key Bindings

Game

Upon selecting "Play" in the main menu, a game of Snake starts immediately with the configured options. The snake advances one cell at a time at regular intervals; the directional keys can be used to change its direction of motion. The goal is to guide the snake to consume fruits (red dots) that randomly appear on the level; eating a fruit increases your score by 1 (displayed at the top of the screen) but also makes the snake longer, making it harder to avoid self-collisions.

Pressing Escape or defocusing the terminal during play will pause the game. While paused, a pop-up menu is displayed, giving you the choice of resuming/unpausing, restarting the game using the same options (though obstacles will be re-randomized), returning to the main menu, or quitting the program.

The game lasts until the snake's head collides with its body, the level border (if the wraparound option was not enabled), or an obstacle, all of which kill the snake. (If you're very skilled, you may also get a game over if you manage to fill the level with the snake.) When the game ends, a message is displayed, and you can choose to start a new game with the same options (by pressing r), return to the main menu (by pressing m), or quit the program (by pressing q).

High scores are tracked and saved to a file automatically (See "Configuration" below). Each combination of game options has its own separate high score. Note that quitting a game in the middle of play will not cause a new high score to be registered.

Configuration File

ratsnake can be configured via a TOML file whose default location depends on your OS:

• Linux — ~/.config/ratsnake/config.toml or $XDG_CONFIG_HOME/ratsnake/config.toml
• macOS — ~/Library/Application Support/ratsnake/config.toml
• Windows — %USERPROFILE%\AppData\Local\ratsnake\config.toml

This file may contain the following tables & keys, all of which are optional unless indicated otherwise:

• [files] — Configure data files

  • high-scores-dir (string) — Path to a directory (which ratsnake will create if it doesn't already exist) in which high scores will be stored. An initial ~/ will be replaced by the path to the user's home directory. The default path is $DATA_DIR/highscores/, where $DATA_DIR is defined below.
  • ignore-errors (boolean) — whether to suppress notifications about any errors that occur while reading or writing the options file or high score file
  • options-file (string or boolean) — File path at which ratsnake will save & restore gameplay options. An initial ~/ will be replaced by the path to the user's home directory. Setting this to false disables saving & loading of options. Setting this to true causes the default path to be used, the same as if the option were omitted. The default path is $DATA_DIR/options.json, where $DATA_DIR is defined below.

• [glyphs] — Set the symbols & colors used to draw various elements of the game display. Each of the below keys takes as its value a subtable containing a required symbol key (a single-column string) and an optional style key (a string as parsed by parse-style). Note that a symbol without a style will be drawn without any styling.

  • collision — Set the symbol & style used when the snake collides with itself, an obstacle, or the level border
  • fruit — Set the symbol & style used for fruit
  • obstacle — Set the symbol & style used for obstacles
  • snake-body — Set the symbol & style used for the parts of the snake's body
  • snake-head — Set the symbol & style used for the snake's head.
    • Unlike the other glyphs, snake-head.symbol may alternatively be set to a table with north, south, east, and west symbol keys (all required), giving the symbols to use for the snake's head when it's moving in the respective directions

• [options] — Set default gameplay options, for use when the options file is absent, disabled, or can't be read

  • fruits (integer from 1 to 10) — how many fruits should be present in a level
  • obstacles (boolean) — whether to generate random obstacles in levels
  • size — set the level size; valid options are "small", "medium", and "large" (case sensitive)
  • wraparound (boolean) — whether levels should wrap around at the borders

The default program configuration is as follows:

[files]
ignore-errors = false

# Linux, with XDG_DATA_HOME not set:
high-scores-dir = "~/.local/share/ratsnake/highscores"
options-file = "~/.local/share/ratsnake/options.json"

# macOS:
#high-scores-dir = "~/Library/Application Support/ratsnake/highscores"
#options-file = "~/Library/Application Support/ratsnake/options.json"

# Windows:
#high-scores-dir = '~\AppData\Local\ratsnake\highscores'
#options-file = '~\AppData\Local\ratsnake\options.json'

[glyphs.snake-head]
symbol = { "north" = "v", south = "^", east = "<", west = ">" }
style = "bold green"

[glyphs.snake-body]
symbol = "\u26AC"
style = "bold green"

[glyphs.fruit]
symbol = "\u25CF"
style = "bright_red"

[glyphs.obstacle]
symbol = "\u2588"
style = "white"

[glyphs.collision]
symbol = "\u00D7"
style = "reversed bright_red"

[options]
wraparound = false
obstacles = false
fruits = 1
size = "large"

Data Directory

By default, options and high scores are saved in a data directory in your home folder, referred to above as $DATA_DIR. The location of this directory depends on your OS:

• Linux — ~/.local/share/ratsnake/ or $XDG_DATA_HOME/ratsnake/
• macOS — ~/Library/Application Support/ratsnake/
• Windows — %USERPROFILE%\AppData\Local\ratsnake\

Acknowledgements

Much of ratsnake's functionality was inspired by nsnake by Alexandre Dantas (no longer maintained).