# File: placeholder.rb
# Purpose: Implementation of the Placeholder class.

require_relative 'unary-element' # Load the superclass


module Macros4Cuke # Module used as a namespace

# Module containing all classes implementing the simple template engine
# used internally in Macros4Cuke. 
module Templating

  # Class used internally by the template engine.  
  # Represents a named placeholder in a template, that is, 
  # a name placed between <..> in the template.  
  # At rendition, a placeholder is replaced by the text value
  # that is associated with it. 
  class Placeholder < UnaryElement

    public

    # Render the placeholder given the passed arguments.
    # This method has the same signature as the {Engine#render} method.
    # @return [String] The text value assigned to the placeholder. 
    #   Returns an empty string when no value is assigned to the placeholder.
    def render(aContextObject, theLocals)
      actual_value = retrieve_value_from(aContextObject, theLocals)
      
      result = case actual_value
        when NilClass
          ''
        
        when Array
          # TODO: Move away from hard-coded separator.
          actual_value.join('<br/>')
          
        when String
          actual_value
        else
          actual_value.to_s
      end
          
      return result
    end  

  end # class

end # module

end # module

# End of file