Module: XMLObject::Properties

Defined in:
lib/xml-object/properties.rb

Instance Method Summary collapse

Instance Method Details

#[](duck) ⇒ Object

Array-bracket ([]) notation access to elements and attributes. Use when the element or attribute you need to reach is not reachable via dot notation (because it’s not a valid method name, or because the method exists, such as id or class).

It also supports a hash key, which is used to reach attributes named the same as elements in the same depth level (which otherwise go first)

All of this is a lot easier to explain by example:

<article id="main_article" author="j-random">
  <author>J. Random Hacker</author>
</article>

article.id                 => 9314390            # Object#id
article[:id]               => "main_article"     # id attribute
article[:author]           => "J. Random Hacker" # <author> element
article[:attr => 'author'] => "j-random"         # author attribute

Valid keys for the hash notation are :attr and :elem.



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# File 'lib/xml-object/properties.rb', line 23

def [](duck)
  if @__target_kid && duck.is_a?(Numeric)
    @__children[@__target_kid][duck]
  elsif duck.is_a?(Hash)
    raise NameError.new('only one key allowed') if duck.keys.size != 1
    key, name = duck.keys[0].to_sym, duck.values[0].to_sym

    unless ( (key == :elem) || (:attr == key) )
      raise NameError.new("Invalid key :#{key.to_s}. Use :elem or :attr")
    end

    value = (key == :elem) ? @__children[name] : @__attributes[name]
    value.nil? ? raise(NameError.new(name.to_s)) : value
  else
    key = duck.to_s.to_sym

    case
      when (not @__children[key].nil?)   then @__children[key]
      when (not @__attributes[key].nil?) then @__attributes[key]
      else raise NameError.new(key.to_s)
    end
  end
end