Interactive tour of the editor!

Motion
------

Like emacs.

Erlang Evaluation
-----------------

In emacs M-: lets you enter a lisp expression in the minibuffer. In ermacs
it lets you enter an erlang expression.

Try it, e.g:

  M-: os:type(). RET

There's also an erlang-interaction-mode. You can enter it by pressing
"C-x i", and get back to Fundamental mode with "C-x f".

Erlang interaction mode is an erlang shell, and its prompt looks like this:

>> foo.

When you press return in Erlang Interaction mode, it evaluates the expression
between the point and the prompt (or start of buffer) and shows the result.

Try it: now press "C-x i". Now press return at the end of the following line:
>> (fun(X) -> X + 5 end)(10).

And now press "C-x f" to get back into fundamental mode.

In erlang-interaction-mode, your history is recorded. You can use:

  M-p: previous input
  M-n: next input
  M-r: regexp search backwards through input history

If you want, you can make this history persistent so that it's stored in a
dets file in your home directory. To do that, go into erlang interaction mode
and hit enter at the end of the following line.

>> edit_var:permanent(erlang_interaction_history, true).

Asynchronous I/O works too:

>> spawn(fun() -> receive after 1000 -> io:format("bar~n") end end).

Erlang Indentation
------------------

The editor can indent erlang code. To enter erlang-mode, press "C-x e". Then
you can hit tab to indent these lines:

one() ->
ok.

two(X) when X > 0,
X < 10 ->
X.

three(X) ->
[Y*2 || Y <- make_list(),
Y < 10].

four() ->
if X == 1 ->
if    Y == 2 ->
ok;
Z == 3 ->
ok
end
end.

five([]) ->
0;
five(List) ->
Sum = lists:foldl(fun(X, Sum) ->
X + Sum
end,
0,
List),
Sum / length(List).

six(X) ->
if X /= 1,
X /= 2 ->
X;
true ->
3
end,
six.

Windows
-------

You can split windows.

Type "C-x 2". Now type "C-x 0".

Notice that if you scroll one window, the other scrolls too. This is a bug :-)

Multiple buffers
----------------

You can use "C-x C-f" to open a new file, and then "C-x b" back here
as you would in emacs (but without the completions).

Other stuff
-----------

To see what else there is, look in the keymap definition:

  C-x C-f ../src/edit_globalmap.erl RET