[Tutor] What are *appropriate* uses for exec() and eval() ?

[boB Stepp]

I have heard periodically about the potential evils of using exec()
and eval(), including today,  on this list. I gather that the first
requirement for safely using these functions is that the passed
argument MUST be from a trusted source. So what would be examples
where the use of these functions IS appropriate?

-- 
boB