RNA Translation Exercise

protein_translation.rb

class InvalidCodonError < ArgumentError; end

module Translation
  def self.of_rna(string)
    result = []
    tris = string.chars
                 .each_slice(3)
                 .to_a
                 .map(&:join)

    tris.each do |tri|
      next_codon = of_codon(tri)

      break if next_codon == 'STOP'
      result << next_codon
    end

    result
  end

  def self.of_codon(tri)
    case tri
    when 'AUG'
      'Methionine'
    when 'UUU', 'UUC'
      'Phenylalanine'
    when 'UUA', 'UUG'
      'Leucine'
    when 'UCU', 'UCC', 'UCA', 'UCG'
      'Serine'
    when 'UAU', 'UAC'
      'Tyrosine'
    when 'UGU', 'UGC'
      'Cysteine'
    when 'UGG'
      'Tryptophan'
    when 'UAA', 'UAG', 'UGA'
      'STOP'
    else
      fail InvalidCodonError
    end
  end
end