Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> Rainer M Krug <Rainer@krugs.de> writes:
>
>> This means *a specific property* - or *any property*? In other words:
>> can property A inherit from one level lower if property B is set in the
>> current level?
>
> It can.

That's good.

>
>> Then I think there is a bug. Look at the following example:
>>
>> #+PROPERTY: header-args  :tangle-mode (identity #o444)
>> #+PROPERTY: header-args+ :eval no-export
>>
>> #+PROPERTY: header-args:R :session *R.EnergyBalance*
>>
>>
>> * Make sure org-use-property-inheritance is nil
>>
>> #+begin_src emacs-lisp
>>  (setq org-use-property-inheritance nil)
>> #+end_src
>>
>> #+RESULTS:
>>
>> Therefore from now on, we will only look at the current level and
>> ignore properties set at lower levels - correct?
>>
>> * Without properties
>> #+begin_src 
>> 13
>> #+end_src
>>
>> ,----
>> | Properties:
>> | 	:header-args 	:tangle-mode (identity #o444) :eval no-export
>> | 	:header-args:nil 	nil
>> | Switches:  
>> | Header Arguments:
>> | 	:cache		no
>> | 	:eval		no-export
>> | 	:exports	code
>> | 	:hlines		no
>> | 	:noweb		no
>> | 	:results	replace
>> | 	:session	none
>> | 	:tangle		no
>> | 	:tangle-mode	292
>> `----
>>
>> * With Properties at level one
>> :PROPERTIES:
>> :header-args+: :tangle SetAtFirstLevel
>> :header-args+: :output-dir ./output
>> :END:
>>
>> #+begin_src R 
>> 13
>> #+end_src
>>
>> ,----
>> | Lang: R
>> | Properties:
>> | 	:header-args 	:tangle-mode (identity #o444) :eval no-export :tangle SetAtFirstLevel :output-dir ./output
>> | 	:header-args:R 	:session *R.EnergyBalance*
>> | Header Arguments:
>> | 	:cache		no
>> | 	:eval		no-export
>> | 	:exports	code
>> | 	:hlines		no
>> | 	:noweb		no
>> | 	:output-dir	./output
>> | 	:results	replace
>> | 	:session	*R.EnergyBalance*
>> | 	:tangle		./output/scripts/analysisCode.do.not.source.R
>> | 	:tangle-mode	292
>> `----
>>
>> ** Second level without properties
>> These should now be the same as [[Without properties]] as org-use-property-inheritance is nil.
>> #+begin_src R 
>> cat(13)
>> #+end_src
>>
>> But it is the same as [[With Properties at level one]].
>> ,----
>> | Lang: R
>> | Properties:
>> | 	:header-args 	:tangle-mode (identity #o444) :eval no-export :tangle SetAtFirstLevel :output-dir ./output
>> | 	:header-args:R 	:session *R.EnergyBalance*
>> | Header Arguments:
>> | 	:cache		no
>> | 	:eval		no-export
>> | 	:exports	code
>> | 	:hlines		no
>> | 	:noweb		no
>> | 	:output-dir	./output
>> | 	:results	replace
>> | 	:session	*R.EnergyBalance*
>> | 	:tangle		./output/scripts/analysisCode.do.not.source.R
>> | 	:tangle-mode	292
>> `----
>
> There's no bug. 
>
> Babel activates inheritance on purpose, no matter what
> `org-use-property-inheritance' says. See the last line of its docstring:
> "ob-core.el" (in particular `org-babel-view-src-block-info') calls
> `org-entry-get' with `t', not `selective'.
>
> Really, `org-use-property-inheritance' is for your own properties. Org
> ignores it to handle its own internal properties.

Ah. That explains.I think it would be quite useful to add this to the
info section of org-use-property-inheritance.

>
>> Concerning property accumulation: I assume you mean the header-args+ -
>> correct? Because I could not find the term "accumu" in the org manual.
>
> Correct.
>
> I don't think they have a name, but they should, because they are
> a different beast than regular properties.
>

I agree - and I like the name "accumulation properties" or "aggregation
properties".


>> Are these properties treated as a normal properties, and the same rules
>> apply, or are there specific rules?
>
> They follow specific rules. For example there can only be one property
> A in a given property drawer, but there can be as many A+ as you want.
> Also, (org-entry-get (point) "A+") will not return something meaningful.

Thanks - things are much clearer now.

So there is no way at the moment to define a property in  lower level
and then overwrite it in a higher level? It might be only me, but I
think that would be quite a useful addition.

Thanks a lot for your help,

Rainer

>
>
> Regards,

-- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

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