advent-of-code-haskell

Introduction

Advent of Code (AoC) occurs over 25 days, with two parts (i.e., problems) given for each day. The executable built in this project, aoc-exe, is meant to make it easier to test solutions to the problems, and for multiple users.

Advent of Code is an Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like. People use them as a speed contest, interview prep, company training, university coursework, practice problems, or to challenge each other.

Usage

Calling the executable aoc-exe with the appropriate arguments and source data saved should compute the solution to an AoC problem.

janey@computer~/advent-of-code-haskell$ stack build
...
janey@computer~/advent-of-code-haskell$ stack exec aoc-exe -- <user> <day> <part>
janey@computer~/advent-of-code-haskell$ <answer>

Arguments

• <user>: identifier of one working on problems (currently, Janey or Thomas)
• <day>: identifier of the problem day (1 to 25 inclusive)
• <part>: identifier of the problem part (1 or 2)

As an example, getting Janey's solution to the Day 1 Part 2 problem would look like this on the command line: stack exec aoc-exe -- Janey 1 2

Types n such

The main function in Main.hs enables the

• capturing of arguments
• parsing of arguments to data structures
• selection of appropriate functions to be applied to output a solution
• handling of errors, malformed arguments, etc

-- <user> argument must be readable as one of the data constructors
data User = Janey | Thomas
- <day> argument must be readable as an Int to satisfy this sum type
newtype Day = Day Int
-- <part> argument, if 1 or 2, is case matched to either constructor
data Part = One | Two

Input data

Even if the arguments to running the executable are well formed, there still may be an error if the input data is not saved, or has an improperly formed name.

Input data should be saved in the inputs directory, in a directory named after the user. Each input data file should be named with the format day<int>-part<int>.

Solution organization

Even if the arguments are well formed and the input data is saved in the proper location with the proper naming, there still may be an unexpected issue. Currently, there is a Map structure called problems that stores details of problems completed and available to be used. When the well-formed arguments are passed to the main function, a lookup is done on the Map for a problem with those identifiers. If the problemID is not found, an error is returned. If the problemID is found, a function (Text -> Text) is returned, and that function is then applied over the appropriate input data set.

TLDR: to use this program appropriately, one needs to update the problems Map in Main.hs with each new problem identifier and the function to be called when that problemID is called.

Motivation

• fun!
• practice!

Future work

• automate/facilitate the updating of the problems Map
• replace the problems map with something else
• track attempts to problems, whether completed/failed, etc