Re: babel header arguments tutorial?

[Nick Dokos <ndokos@gmail.com>]

Thomas S. Dye <tsd@tsdye.com> writes:

> Aloha Nick,
>
> Nick Dokos <ndokos@gmail.com> writes:
>
>> The implementation on the page you linked contains a typo (capital P
>> instead of lower-case p in python) and is much more prolix than it needs
>> to be. You can get the same effect with
>>
>> # Local Variables:
>> # org-babel-default-header-args:python: ((:session . "foo")))
>> # End:
>>
>> This form should be preferred for just setting variables. The eval
>> mechanism should be used only when absolutely necessary.
>
> Can you elaborate why the eval mechanism should be used only when
> absolutely necessary?  You've mentioned that a few times but I haven't
> run across similar warnings elsewhere.
>

It's a matter of safety: eval allows you to evaluate arbitrary lisp
code. Doing that in a local-variables block which is run when you
open the file can lead to all kinds of damage. If you get a file
with an eval in the local variables section, you'd better be very
sure before opening the file in emacs.

Here's one warning:

http://www.gnu.org/software/emacs/manual/html_node/emacs/Safe-File-Variables.html

-- 
Nick