class Arel::Nodes::BoundSqlLiteral

def +(other)
  raise ArgumentError, "Expected Arel node" unless Arel.arel_node?(other)
  Fragments.new([self, other])
end

def eql?(other)
  self.class == other.class &&
    sql_with_placeholders == other.sql_with_placeholders &&
    positional_binds == other.positional_binds &&
    named_binds == other.named_binds
end

def hash
  [self.class, sql_with_placeholders, positional_binds, named_binds].hash
end

def initialize(sql_with_placeholders, positional_binds, named_binds)
  if !positional_binds.empty? && !named_binds.empty?
    raise BindError.new("cannot mix positional and named binds", sql_with_placeholders)
  elsif !positional_binds.empty?
    if positional_binds.size != (expected = sql_with_placeholders.count("?"))
      raise BindError.new("wrong number of bind variables (#{positional_binds.size} for #{expected})", sql_with_placeholders)
    end
  elsif !named_binds.empty?
    tokens_in_string = sql_with_placeholders.scan(/:(?<!::)([a-zA-Z]\w*)/).flatten.map(&:to_sym).uniq
    tokens_in_hash = named_binds.keys.map(&:to_sym).uniq
    if !(missing = (tokens_in_string - tokens_in_hash)).empty?
      if missing.size == 1
        raise BindError.new("missing value for #{missing.first.inspect}", sql_with_placeholders)
      else
        raise BindError.new("missing values for #{missing.inspect}", sql_with_placeholders)
      end
    end
  end
  @sql_with_placeholders = sql_with_placeholders
  if !positional_binds.empty?
    @positional_binds = positional_binds
    @named_binds = nil
  else
    @positional_binds = nil
    @named_binds = named_binds
  end
end

def inspect
  "#<#{self.class.name} #{sql_with_placeholders.inspect} #{(named_binds || positional_binds).inspect}>"
end