Ruby 为什么我会得到一个命名者？

当我试着用say运行它时

class UnitCircle
    def prompt
        puts "Enter a number: "
        @number = gets
        @number = @number.to_i
        puts "Enter a trigonometric equation to perform on that number: "
        @eqn = gets
    end
end
uc = UnitCircle.new
uc.prompt
num = Math.send(uc.instance_eval {@eqn}, uc.instance_eval {@number})

我得到一个无方法错误，为什么

@number = 30
@eqn = sin

获取

方法将包括新行符号“\n”。所以你必须

chomp

it。 如果不选择chomp，则最终将调用方法“sin\n”而不是“sin”

class UnitCircle
    def prompt
        puts "Enter a number: "
        @number = gets.chomp
        @number = @number.to_i
        puts "Enter a trigonometric equation to perform on that number: "
        @eqn = gets.chomp
    end
end