Re: [O] About commit named "Allow multi-line properties to be specified in property blocks"

[Eric Schulte]

Nicolas Goaziou <address@hidden> writes:

> Eric Schulte <address@hidden> writes:
>
>> The only problem with a single #+PROPERTY: line is that this line could
>> become unreadably long.  By allowing such an entry to span multiple
>> lines it becomes feasible to chain together many variables into a single
>> property.  Another approach which is easily implementable would be to
>> use syntax like the following...
>>
>>
>>   #+PROPERTY:  var foo=1,
>>   #+PROPERTY+:     bar=2,
>>   #+PROPERTY+:     baz=3,
>>   #+PROPERTY+:     qux=4
>
> Well, what about:
>
> #+property: :var foo=1
> #+property: :var bar=2
> #+property: :var baz=3
> #+property: :var qux=4
>
> Sure, we repeat ":var" more times, but at least, it's consistent with
> the rest of Org.
>

Unfortunately this won't work, the final value of the "var" property
will be "qux=4" rather than "foo=1, bar=2, baz=3, qux=4".

>
>> Although I originally switched from the above to the implemented
>> because I thought that using a block would be more consistent with
>> Org-mode syntax.
>
> No, as I said, no block has ever controlled Org internals. That's a job
> for keywords and property drawers.
>

I would say that the block is defining an keyword, but yes, I suppose
we've never had a multi-line keyword definition structure.

>
>> Also, the above is undesirable in its requires the PROPERTY+ lines to
>> care about their position in the Org-mode file, which isn't normally
>> the case.
>
> Yes, "#+property+:" would be atypical in that situation.
>
>> I think of #+FOO: lines as containers for anything that fits on
>> a single line, and as blocks as containers for anything that requires
>> a line break, e.g., #+HTML and #+BEGIN_HTML/#+END_HTML.
>
> That comparison with "#+html" and "#+begin_html" doesn't hold as most
> "#+keyword:" syntax don't have an equivalent block "#+begin_keyword",

Along these lines I would also like to allow TBLFM lines to be broken
over multiple lines, as I often find myself right-scrolling in a buffer
to find equations in large spreadsheets.  I wonder if there would be a
general solution to allow *all* #keyword+ lines to have a block
equivalent.

> 
> and the other way. Look again at every block type in Org, and see if
> there's any equivalent use of the "#+begin_property" you're
> introducing.  I don't think so.
>

agreed

>
> Moreover, some keywords can be repeated on multiple lines. Think about
> "#+text:" before first headline, or "#+header:" before a src block. So,
> clearly, "#+keyword:" isn't just about things that must fit on a single
> line.
>

I don't know how #+text: works, but with #+header: the order of the
blocks is not important, i.e.,

#+headers: :var a=1
#+headers: :cache a=2

is equal to

#+headers: :cache a=2
#+headers: :var a=1

but the same is not true for

#+PROPERTY:  var foo=1,
#+PROPERTY+:     bar=2

and

#+PROPERTY+:     bar=2
#+PROPERTY:  var foo=1,

>
> Also, you don't really need a line break here, since you will eventually
> parse the values line by line anyway, and not as a block or a paragraph.
>
> You want to add syntactic sugar. There's nothing wrong with it though,
> but not everyone appreciate aspartame ;)
>

Yes, if you dig way back into this thread you'll see the motivation,
basically there are times when a user will want to specify *many*
variables in a single property specification.  If there is a more
natural syntax I am very open to suggestions.

>
>> I didn't realize that there was an extra semantics of blocks as
>> formatting, and I'm not sure if such an association is desirable or
>> intentional.
>
> It is desirable to have a logic behind syntax, and to always refer to
> it. Thus, is is desirable to separate syntax used for contents from
> syntax used for Org control. It's very different from "things on
> a single line vs things on multiple lines".
>

Sure, but to play devils (or my own) advocate, I would say that
simplicity is important and "blocks for multi-line content" is a simpler
rule than "blocks for formatting of multi-line content, and for naming
multi-line data", the second being the case with code and example
blocks.

My goal here is to find the most natural solution which conforms to
Org-modes design as well as possible, I just don't know what that would
be...

Cheers -- Eric

>
>
> Regards,

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