Profile include support, round 2

[Greg Hudson]

On Thu, 2010-08-26 at 02:29 -0400, Danilo Almeida wrote:
> I am not convinced that allowing an include in the middle of parsing a
> section is a good idea.
[...]
> If we do want to disallow the above [...]

It would not be difficult, but I'd prefer not to.

By making included files syntactically independent of their parents,
we've removed pretty much all of the "attractive but pathological" use
cases.  Adding additional restrictions means creating more error codes
and more error-handling code without, in my opinion, protecting the
admin from any likely mistakes.

Ezra wrote:
> The biggest danger in my mind on allowing an include in the middle of
> a section is what happens if someone forgets to close a brace before
> the include.

Remember, we've ditched the preprocessor model of profile includes.  So
if you forget to close a brace before the include, relations defined
within the included file will not show up within the braced group.