问题 I try to write a simple function to provide me with a random letter each time i call it but I have difficulties combining my idea with the concept of a functional programing approach. Some help along the way would be appreciated! The code I have looks like: <xd:doc> <xd:desc>Provides one random letter, if the type is provided it returns a letter of thet type</xd:desc> <xd:param name="type">The type of letter to return, one of (A,a,B,b)</xd:param> </xd:doc> <xsl:function name="gdpr