Advent of Code for Haskell

This repository is a GitHub template for Advent of Code solutions in Haskell. It provides a simple CLI tool and VSCode tasks to streamline your Advent of Code experience in Haskell, without the need to learn cabal and with a sensible set of packages.

Features

• A sensible set of dependencies for AoC.
• A bash command-line interface (CLI) that allows you to:
  • Create Haskell files for each new Advent of Code day.
  • Run solutions for each day with ease.
  • Automatically manage Cabal files, reducing setup hassles.
• VSCode tasks for seamless interaction with the CLI.

Getting Started

To get started with Advent of Code in Haskell using this template:

1. Install your Haskell tooling via ghcup.

2. Click on "Use this Template" to create a new project/repository based on this template.

3. Clone the newly created repository to your local machine:

   git clone https://github.com/<yourusername>/your-new-project.git
   cd your-new-project

4. Optionally, create an .env file with your Advent of Code session cookie. If you're unsure how to obtain the cookie, check this guide. If you don't create an .env file you'll be prompted to provided the cookie.

   AOC_SESSION=your-cookie-here

5. Create day-1 files. You can do this in one of two ways:

   • Via the CLI: Run ./aoc-hs new -d 1 (you may need to run chmod +x aoc-hs before this).
   • Via VSCode tasks: Press CTRL+Shift+P, type "Run Task," and select "create new day template." Follow the instructions.

After following these steps, you'll find newly created folders named solutions and inputs in your project directory. Files input/day-x.input should contain your personal AoC input and input/day-x.example should be empty. You can copy paste the public example given by AoC in those .example files

Start Coding. Probably you have to wait a little bit for HLS to download and build some dependencies the first time you open the project.

CLI Usage

Here's how to use the CLI for common tasks:

• Create a new solution for a specific day:

  ./aoc-hs new -d <day>

• Run a solution for a specific day and part:

  ./aoc-hs run -d <day> -p <part> --input

Below there is the complete description of the CLI (you can run ./aoc-hs --help to get it in you local machine):

Usage: aoc-hs [new -d <day> [--no-curl] | run -d <day> -p <part> [-f <file-name> | --example | -e | --input | -i]]

Description:
  This tool simplifies Advent of Code solutions in Haskell by creating templates and handling input files. No need to learn Cabal!

Subcommand: new

Create a new Advent of Code solution for the specified day. It creates a main module, modifies the .cabal file, and downloads the input data.

Usage: aoc-hs new -d <day>
Example: aoc-hs new -d 3
         aoc-hs new -d 3 --no-curl
Options:
  -d <day>       Specify the day for the Advent of Code puzzle (1-25).
  --no-curl      It wont download your personal AoC input file. You don't have you provide a cookie with this option

Subcommand: run

Run an Advent of Code solution for the specified day and part. The input data is read from a file which can be supplied via -f or you can 
use shortcuts --example and --input. Default --input

Usage: aoc-hs run -d <day> -p <part> [-f <file-name> | --example | -e | --input | -i]
Example: aoc-hs run -d 3 -p 2 --example
         aoc-hs run -d 3 -p 3 -e
         aoc-hs run -d 3 -p 2 --input
         aoc-hs run -d 3 -p 2 -i
         aoc-hs run -d 3 -p 2 -f my-input-file.txt
Options:
  -d <day>       Specify the day for the Advent of Code puzzle (1-25).
  -p <part>      Specify the part of the puzzle (1 or 2).
  -f <file-name> Specify a custom input file to use.
  --example, -e  Use the example input file (./inputs/day-<day>.example) as input.
  --input, -i    (Default) Use the puzzle input file (./inputs/day-<day>.input) as input.

Haskell details

After running ./aoc-hs new -d x, you'll find files day-x.hs in the solutions folder. Such files should contain the haskell code for that day. Each day is built as an stand alone executable, so code isn't shared between two days. In practise, this is not a problem since it is rare that AoC days requiere code sharing. Each executable depends on these libraries:

• attoparsec: for parsing inputs
• base >=4.7 && <5: the base package
• bytestring: bytestring is the string format used by attoparsec
• containers: containers for generic containers like Map, Set, etc...
• matrix: because AoC love two-dimensional discrete problems
• vector: Int based array. Oftenly a replacement for Haskell's Lists
• split: algorithms to split lists
• search-algorithms: a blessed interface to bfs, dfs, dijkstra, etc...
• mtl: Just in case you need the state monad
• pointedlist: because AoC loves circual arrays.
• bytestring-trie bytestring based Trie for searching string problems.

The dependencies are chosen to match a typical AoC season.

With Respect to hls, there is an explicit hie.yaml just in case. I've had problems in the past with common stanzas.

Contributing

Contributions are welcome! If you encounter any issues or have suggestions for improvements, please open an issue or submit a pull request.

License

This project is licensed under the WTFPL License - see the LICENSE file for details.