class Arel::Nodes::Function

def as(aliaz)
  self.alias = SqlLiteral.new(aliaz)
  self
end

def eql?(other)
  self.class == other.class &&
    self.expressions == other.expressions &&
    self.alias == other.alias &&
    self.distinct == other.distinct
end

def hash
  [@expressions, @alias, @distinct].hash
end

def initialize(expr, aliaz = nil)
  super()
  @expressions = expr
  @alias       = aliaz && SqlLiteral.new(aliaz)
  @distinct    = false
end