Advent of Code 2023 Day 1

day_one.rb

#!/usr/bin/env ruby

input = File.read('day_one.input')

Token = Data.define(:forward, :backward)
Tokens = {
  eightwo:   Token[8, 2],
  eighthree: Token[8, 3],
  fiveight:  Token[5, 8],
  nineight:  Token[9, 8],
  oneight:   Token[1, 8],
  sevenine:  Token[7, 9],
  threeight: Token[3, 8],
  twone:     Token[2, 1],
  '1':       Token[1, 1],
  '2':       Token[2, 2],
  '3':       Token[3, 3],
  '4':       Token[4, 4],
  '5':       Token[5, 5],
  '6':       Token[6, 6],
  '7':       Token[7, 7],
  '8':       Token[8, 8],
  '9':       Token[9, 9],
  one:       Token[1, 1],
  two:       Token[2, 2],
  three:     Token[3, 3],
  four:      Token[4, 4],
  five:      Token[5, 5],
  six:       Token[6, 6],
  seven:     Token[7, 7],
  eight:     Token[8, 8],
  nine:      Token[9, 9]
}

Regex = Regexp.new(Tokens.keys.join('|'))

result = input.split("\n").map do |line|
  symbols = line.scan(Regex).map(&:to_sym)
  tokens = symbols.map{ |symbol| Tokens[symbol] }

  [tokens.first.forward, tokens.last.backward].join.to_i
end.sum

puts result