Properties Drawer versus tags

Properties Drawer versus tags

[Lawrence Bottorff]

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Very simple, largely philosophical question: When/why use a properties
drawer below a heading versus just using tags on the heading? What are the
advantages, disadvantages of both?

LB

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Re: Properties Drawer versus tags

[David R]

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I forgot something important, part of "the case in favor of properties":

It's sometimes useful to be able to search for a category or sort by a
category. It's harder to do that if you haven't explicitly entered that
category anywhere.

-- 
-- 
David Rogers

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Fwd: Properties Drawer versus tags

[David R]

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---------- Forwarded message ----------
From: David R <davidandrewrogers@gmail.com>
Date: Thursday, December 19, 2019
Subject: Properties Drawer versus tags
To: Lawrence Bottorff <borgauf@gmail.com>




On Thursday, December 19, 2019, Lawrence Bottorff <borgauf@gmail.com> wrote:
> Very simple, largely philosophical question: When/why use a properties
drawer below a heading versus just using tags on the heading? What are the
advantages, disadvantages of both?
> LB

At the most basic level, the difference is simple: Properties connect two
ideas, while tags are each a single idea.

Properties often show a category along with a fact that belongs in that
category, such as "Book type" - "Fiction".

If you have several categories that continually come up, and those
categories will have various facts tied to them, then you probably want
properties. But if the categories are inconsistent from item to item, or if
the categories don't matter and you only need the individual facts, then
tags may make more sense.

And there's nothing to stop you from using both.

--
David Rogers



-- 
-- 
David Rogers

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Re: Properties Drawer versus tags

[Allen Li]

On Fri, Dec 20, 2019 at 3:25 PM Lawrence Bottorff <borgauf@gmail.com> wrote:
>
> Very simple, largely philosophical question: When/why use a properties drawer below a heading versus just using tags on the heading? What are the advantages, disadvantages of both?

I believe tag filtering has better performance than property
filtering.  Also, I think that tags were initially designed/intended
primarily for filtering in agenda views (more wizened users can
correct me on both points).

Tags also have better visibility, as they are visible by default on
each heading line in the buffer and in the agenda.

>
> LB

Re: Properties Drawer versus tags

[Ken Mankoff]

On 2019-12-19 at 22:24 -08, Lawrence Bottorff <borgauf@gmail.com>
wrote...
> Very simple, largely philosophical question: When/why use a properties
> drawer below a heading versus just using tags on the heading? What are
> the advantages, disadvantages of both?

Tags are binary. They are there or not.

Property drawers allow you to assign values to variables.

I've never fully understood why some property drawers are set to binary. For controlling LaTeX export I have both a property ":clearpage: t" and a tag ":ignore:", and the tag makes more sense to me. Some of those may only exist in my personal config.

  -k.

Re: Properties Drawer versus tags

[Lawrence Bottorff]

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I might add that a properties/drawer is a sort of "official heading
metadata repo," while tags not so much. It would be nice to see (lots of)
examples.

On Fri, Dec 20, 2019 at 9:18 AM Ken Mankoff <mankoff@gmail.com> wrote:

>
> On 2019-12-19 at 22:24 -08, Lawrence Bottorff <borgauf@gmail.com>
> wrote...
> > Very simple, largely philosophical question: When/why use a properties
> > drawer below a heading versus just using tags on the heading? What are
> > the advantages, disadvantages of both?
>
> Tags are binary. They are there or not.
>
> Property drawers allow you to assign values to variables.
>
> I've never fully understood why some property drawers are set to binary.
> For controlling LaTeX export I have both a property ":clearpage: t" and a
> tag ":ignore:", and the tag makes more sense to me. Some of those may only
> exist in my personal config.
>
>   -k.
>

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Re: Properties Drawer versus tags

[Adam Porter]

I'll try to explain my view of tags.  Let's see if it makes sense.  :)

Conceptually, properties are like a generic key-value store for
headings, and tags are like a certain property.  Imagine if, instead of
tags being placed in headings, like this:

  * Blueberries  :food:fruit:

...tags were implemented as properties, like this:

  * Blueberries
  :PROPERTIES:
  :TAGS: food fruit
  :END:

The meaning would be essentially the same.

From a technical perspective, putting tags on headings makes them much
faster to search for, because a regexp can be used to search directly to
them (local ones, anyway).  In contrast, to find the next location of a
certain property, a single regexp search is not enough, because even if
a regexp search was done to find an entry like the previous example,
like:

  (re-search-forward
    (rx bol ":TAGS:" (1+ blank) (0+ nonl) bow "food" eow)
    nil t)

...it would not be guaranteed that the result would actually be in a
heading's property drawer, so additional checks must be done to ensure
that.

Some properties are special, like CATEGORY.  As well, some properties
are "virtual," like SCHEDULED, which is written like:

  * Heading
  SCHEDULED: <2019-12-20 Fri 11:00>

...but is accessible with org-entry-get, like a property in a drawer.

So, use tags for applying simple, conceptual labels to headings, because
they're faster to search for than properties and always visible.  Use
properties as a key-value store for details that are less likely to be
used in a query and are less important to see.

What do you think?  :)