[quarterwave]

Is there an Erlang shell to evaluate expressions?

There seems to be a sub-window to the right of the module editor, but I'm unable to place the cursor there.

Tried in both Firefox 35 and Chrome 39.

[seriyPS]

No, there is no shell. Only main() function can be evaluated. You may be interested in http://tryerlang.org/, but it is much more restricted.

I don't understand about which window you are talking about. May you make a screenshot?

[Attic]

I think he might be referring to the 80 column vertical line

[quarterwave]

That's correct, thanks for pointing it out.