Forum:Template Condition A and B or C

How can I write the following conditions in a template:

IF Parameter A is defined AND (Parameter B >= 5 OR Parameter C contains the string gota"boy!) --MyBrute Resource Center@Ronga 11:09, 16 May 2009 (UTC)
 * Returns true
 * Returns false


 * mw:Help:Extension:ParserFunctions. 13:25, 16 May 2009 (UTC)