context_and_service.rb

class PrintLineService
  def initialize(context)
    @context = context
  end
  
  def call
    puts @context.line
  end
end

class ContextFromArray
  def initialize(arr)
    @line = arr.join(', ')
  end
  def line
    @line
  end
end

class ContextFromLine
  def initialize(line)
    @line = line
  end
  def line
    @line
  end
end

# Используется примерно так:
c1 = ContextFromArray(['hello', 'world'])
PrintLineService.new(c1).call
# Возвращает 'Hello, world'
c2 = ContextFromLine.new('Bye, world')
PrintLineService.new(c2).call
# Возвращает 'Bye, world'