module MasterView
  module Directives

    # takes the attr_value and parses it as a hash :foo => 'bar', :baz => 'cat'
    # it sets/overrides the tag's attribute values for each value.
    # To use erb output simply wrap the content in #{ foo } for example :foo => #{h product.name}
    # 
    class Attr < MasterView::DirectiveBase
      # substitution to make it easy to parse erb in attr
      SubstForErb = '#'+InlineErbStart+'= \1 '+InlineErbEnd+'#'

      metadata :priority => 'MediumLow',
        :category => 'general',
        :description => 'Replaces attribute value(s) on an element with the value of an expression'

      event :stag do
        attr_value.gsub!( /#\{([^}]*)\}/, SubstForErb ) #taking #{h product.name} and changing to #{{{= h product.name}}}# for easy parsing
        arr = attr_value.scan( /:(\w+)\s*=>\s*(['"#])([^,\2]*)\2,?/  )
        arr.each do |scn|
          n = scn[0]
          v = scn[2]
          element_attrs[n] = v
        end
      end

    end
  end
end