Help:Parser functions in templates

When applying ParserFunctions to template parameters, a pipe symbol ("|") may be used to provide the empty string as default value, in order to indicate how to handle things if a parameter is or is not passed in.


 *  


 * Sample A:  


 * Result: 


 *  


 * Sample B:  


 * Result: 


 * Comparison

The second usage is often the desired way to handle situations where a parameter exists, but is comprised only of empty space.