Re: About the use of PROPERTY "meta lines"...

[Eric Schulte <eric.schulte@gmx.com>]

"Sebastien Vauban" <wxhgmqzgwmuf@spammotel.com> writes:

> Hi Eric and all,
>
> Eric Schulte wrote:
>> "Sebastien Vauban" <wxhgmqzgwmuf@spammotel.com> writes:
>>
>>> #+TITLE:     Properties
>>> #+AUTHOR:    Seb Vauban
>>> #+PROPERTY: var  foo=1
>>> #+PROPERTY: var+ bar=2
>>>
>>> * Abstract
>>>
>>> IIUC, properties are set in this way:
>>>
>>> - on a file basis, before any heading, through the =PROPERTY= keyword,
>>> - on a subtree basis, through the =PROPERTIES= block.
>>>
>>> My comprehension is that the =PROPERTY= keyword may not be used inside "trees",
>>> and should be ignored if that would happen.
>>
>> While it is not normal usage, I think that it is legal for #+PROPERTY:
>> lines (or #+Option: lines etc...) to appear inside of subtrees.
>
> I realize this is not especially a Babel question, but more a Org core
> question...
>
> Thanks for your answer -- which generates a new one, though: what is then the
> expected *semantics* of such a construct?
>
> There are at least 3 different views on such a construct: putting a PROPERTY
> line inside a subtree...
>
> - ... resets some values from that point up to the end of the subtree
> - ... resets some values from that point up to the end of the buffer
> - ... defines some values which can have already been by the subtree
>

I agree this is murky and whatever behavior we want should be clearly
thought out and documented in the manual.  I would argue that you missed
another possible semantics, the simple semantics which are currently
implemented in which a property line *anywhere* in a buffer sets a
global property.

Cheers,

>
> Best regards,
>   Seb
>
>>> The following example shows that either:
>>>
>>> - I'm wrong to think so,
>>> - there is a bug.
>>>
>>> What is the right assumption here?
>>>
>>> * Subtree
>>>
>>> Being located in a subtree, the following lines are ill-placed IMHO:
>>>
>>> #+PROPERTY: var  foo="Hello
>>> #+PROPERTY: var+ world"
>>>
>>> Though, they're well taken into account:
>>>
>>> #+begin_src emacs-lisp
>>>   foo
>>> #+end_src
>>>
>>> #+results:
>>> : Hello world
>>>
>>> These lines have even wiped the definition of =bar= (because of the use of =var=
>>> without any =+=):
>>>
>>> #+begin_src emacs-lisp
>>>   (+ foo bar)
>>> #+end_src
>>>
>>> returns the error "Symbol's value as variable is void: bar."

-- 
Eric Schulte
http://cs.unm.edu/~eschulte/