Re: 1.5: Discuss link characteristics?

At 05:13 PM 02/09/97 -0800, Jon Bosak wrote:

>Instead of the two categories "4. link formatting" and "5. link
>behavior", which I don't think are separable, make a single item
>number 4, "link behavior", and then distinguish between two categories
>of behavior, link display and link traversal, as follows:
>A. Link display
>   How termini are presented to the user.
>   - Possibly conditioned on history
>   - Possibly including (e.g.) menus to display alternative link
>     target labels ("explainers"), termini represented as animated
>     figures, etc. as well as the usual underlining, etc.
>B. Link traversal
>   What happens when a link is traversed.
>   - Effects when traversed: opening/closing windows, scrolling,
>     displaying data from termini in various ways (including the
>     automatic transclusion of data without user action)
>   - Testing, authenticating, and logging user context information
>   - Running programs

Here, here.

On the other hand, Martin wrote a distinction between behavior and
presentation that I think wrongly conflates two axes: 

   1) user vs. author control, and 

   2) geometric layour versus what happens on mouse-click

You can't completely separate formatting behavior from interaction behavior,
and you sure can't combine those two axes.

Example: there's a quotation element. I, as a user, may want it:

   * Displayed in a footer or sider pane

   * Rendered as an inline block-quotish kind of layout

   * Hidden behind something clickable like an icon or a footnote number,
     and displayed on demand.

   * Hidden per last point, but in big pink type if I reached it via a link
     or type 'criticism' and small green if by a link of type 'support'.

   * flagged for different indexing treatment, or extracted along with all
     others of its kind to make a biblio.

Now try to pin down just which of those are presentation and which are
behavior. And then convince all the users that they only ever want control
of presentations, and convince all the authors that they only ever want
control of behavior.

In *every* presentation, I may want to associate behavior. For example, when
it's inline I may want to be able to click on it anyway, and retrieve the
source being quoted. Or maybe I want my display of the quotation to have a
scrollbar, so without following any link I can just scroll around to see its
original context. 

I do not think it is possible to make a *principled* distinction between
formatting behavior and interactive behavior. And they do not correlate
precisely with the entirely separate notion of user vs. author control. If
we conflate those two separate axes, we'll just impose a needless limitation.

And Murray wrote:
>But in no case does clicking on a link take the user to a _different_
>location than that intended by the author, and I believe this is the crux
>of the issue. There are two behaviours here: link destination and browser
>action. In no case should the browser alter the former.

I find that tempting, but a bit too strong. There are at least a few cases
where the destination depends on other factors, such as implicit links,
links that depend on user configuration or environment data, etc. Take a
look at any IETM, or any expert-system-assisted maintenance manual, or
anything that supports stretchtext.