Conditional query chaining in Rails 3

conditional_chaining_with_tap.rb

# I want a list of 6 non-administrators who are not the
# current user only if someone is logged in. Otherwise,
# don't check current_user's id.

# instead of this:

if user_signed_in?
  @other_users = User.non_admin.limit(6).where("name IS NOT NULL")
else
  @other_users = User.non_admin.limit(6).where(['id != ?', @user.id]).where("name IS NOT NULL")
end

# I can write:

@other_users = User.non_admin.limit(6).tap {|query|
  query.where(['id != ?', @user.id]) if user_signed_in?
}.where("name IS NOT NULL")

# The "if user_signed_in?" inside the tap block means I am
# conditionally modifying the query midstream. The same
# object is passed out the other side of the tap statement
# whether or not the additional .where is ever evaluated.