class String
  def from_csv(sep = /,/)
    ret = chomp.split(sep)
    idx = 0;
    while idx < ret.length do
      if ret[idx][0] == "\""[0]
        while ret[idx][-1] != "\""[0]
          raise "Unterminated quote" if idx+1 >= ret.length
          ret[idx] = ret[idx]+","+ret[idx+1]
          ret.delete_at(idx+1)
        end
        ret[idx] = ret[idx].sub(/^"/, "").sub(/"$/, "")
      end
      idx += 1
    end
    ret
  end
end

class Array
  def from_csv
    self.map { |l| l.to_s.chomp.from_csv }
  end

  def to_csv(f)
    File.open(f, "w+") { |f| each { |row| f.puts(row.join(',')) }}
  end
end

class IO
  def from_csv(args = {})
    header = args.fetch(:header, false)
    separator = args.fetch(:separator, /,/)
    keys = readline.chomp.
              sub(/ *$/, "").sub(/^ */,"").
              from_csv(separator) if header;
    map { |l| l.to_s.chomp.from_csv(separator) }.
      map { |a| if header then keys.zip(a).to_h else a end }
  end
end

class File
  def File.csv(f, args = {})
    File.open(f) {|io| io.from_csv(args) }
  end
end