# File lib/parslet/pattern.rb, line 73
  def element_match_binding(tree, exp, bindings)
    var_name = exp.variable_name

    # TODO test for the hidden :_ feature.
    if var_name && bound_value = bindings[var_name]
      return bound_value == tree
    end
    
    # New binding: 
    bindings.store var_name, tree
    
    return true
  end