class Sass::Value::Calculation

def ==(other)
  other.is_a?(Sass::Value::Calculation) &&
    other.name == name &&
    other.arguments == arguments
end

def assert_calculation(_name = nil)
  self
end

def calc(argument)
  new('calc', [argument])
end

def clamp(min, value = nil, max = nil)
  if (value.nil? && !valid_clamp_arg?(min)) ||
     (max.nil? && [min, value].none? { |x| x && valid_clamp_arg?(x) })
    raise Sass::ScriptError, 'Argument must be an unquoted SassString.'
  end
  new('clamp', [min, value, max].compact)
end

def hash
  @hash ||= [name, *arguments].hash
end

def initialize(name, arguments)
  arguments.each do |value|
    assert_calculation_value(value)
  end
  @name = name.freeze
  @arguments = arguments.freeze
end

def max(arguments)
  new('max', arguments)
end

def min(arguments)
  new('min', arguments)
end

def valid_clamp_arg?(value)
  value.is_a?(Sass::Value::String) && !value.quoted?
end