Question

我创建了log_slow别名，但它无效：

require 'bigdecimal'
require 'bigdecimal/math'
require 'bigdecimal/util'

module BigMath
  alias :log :log_slow
  def log(x, prec)
    if x <= 0 || prec <= 0
      raise ArgumentError, "Zero or negative argument for log"
    end
    return x if x.infinite? || x.nan?
    sign, fraction, power, exponent = x.split
    fraction = BigDecimal(".#{fraction}")
    power = power.to_s.to_d
    log_slow(fraction, prec) + (log_slow(power, prec) * exponent)
  end
end

include BigMath
number = BigDecimal("1234.5678")
Math.log(number)
prec = 50
puts BigMath.log_slow(number, prec).round(prec).to_s("F")
puts BigMath.log(number, prec).round(prec).to_s("F")
puts BigMath.log(number ** 1000, prec).round(prec).to_s("F")

我收到错误：

in `<module:BigMath>': undefined method `log_slow' for module `BigMath' (NameError)

Answer 1

您的别名应该是这样的，以逃避错误

module BigMath

    def log(x, prec)
      #your code
    end


   alias log_slow log
end

格式：

alias new_name old_name

Ruby BigDecimal方法错误

1 个答案: