System.sink & System.lent

[exelotl]

For me it comes down to the "use the least powerful tool for the job" mantra 
(especially when writing code that might be used by other people) - procs are 
simpler and more constrained in what they can do. When they contain errors or 
are used wrongly they will often fail earlier in the compilation process and 
produce better error messages. So if a proc will do the job, use a proc.