Is functional programming difficult to learn/teach?

[Drakain Zeil]

I would say it depends on the person's background knowledge. For example, explaining a programming function is much easier if you have a background knowledge of things like...

f(x)=20x+x/10
g(x)=10
h(x)=109*f(x)/g(x)

...for example.

Chances are, if you know what those mean, and can easily make use of them, you'll be better capable of understanding how functions work (even ones with more than one argument, since that concept is easily transferable).

However, if the sight of those compleatly flabergast you, you would have a harder time understanding it.

[wtd]

Well, it also depends on how you explain functions to students.

Are functions names for some place in memory that you can execute, optionally pushing arguments onto the stack which can be popped off and used?

Well, of course it is. But... is that how you explain it?

Or, do you explain that a function is a relationship which maps its arguments onto a new value, and may be implemented as mentioned above?