How to add a vertical line?

Hi!

I am writing a program which reads data from a file and then plots it
as an XYSeries. Now the problem is that I want to add a vertical line
at 1/e

How to do it without? Is this functionality already available or there
is some way? For example, I can plot a line from (1/e, -100) to (1/e,
100). But this disrupts the automatic bounds of range axis :(

-- 
Anupam Srivastava
-----------------
[Isaac Newton falls off the tree]

Cho-Cho: Did the fall hurt you?
Newton: It wasn't the fall; it was the sudden stop at the end.

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