Advent of Code 2024 - Day 3

Learning Questions & Discussions Coding Challenges
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22

I used NimbleParsec to build a parser:

defmodule Parser do
  import NimbleParsec

  disable =
    ignore(string("don't()"))
    |> tag(:disable)

  enable =
    ignore(string("do()"))
    |> tag(:enable)

  operand = integer(max: 3, min: 1)

  mul =
    ignore(string("mul("))
    |> concat(operand)
    |> ignore(string(","))
    |> concat(operand)
    |> ignore(string(")"))
    |> tag(:mul)

  instruction = choice([disable, enable, mul])

  instructions =
    eventually(instruction)
    |> repeat()

  defparsec(:parse, instructions |> eventually(eos()))
end
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