Questions about TAB in 3.0

Evan Kirshenbaum (evan@hplerk.hpl.hp.com)
Sun, 26 Mar 95 02:36:23 EST

A few questions about the TAB element in the recent (3/21) 3.0 DTD:

- I was going to suggest that it would be useful to add a LEADER
element to specify filling with dots or dashes, but it dawned on
me that this sort of markup was more properly handled by style
sheets. Unfortunately, TAB does not take a CLASS attribute. Is
there a reason for this omission?

- What exactly is the intended use model for decimal tabs? I can
think of several possibilities:

1. <tab id=try1 align=decimal dp=".">123.45
<tab to=try1>2.50

2. 123<tab id=try2 align=decimal dp=".">.45
<tab to=try2>2.50

3. 123.<tab id=try3 align=decimal dp=".">45
<tab to=try3>2.50

4. 123<tab id=try4>.45
<tab to=try4 align=decimal dp=".">2.50

5. 123.<tab id=try5>45
<tab to=try5 align=decimal dp=".">2.50

My own preference would be for (4).

- When tabbing to a tab stop within an environment that has
different prevailing margins is the position tabbed to relative to
the prevailing margin or the window?

- When the INDENT attribute is used, is the intended semantics to
insert the specified space and then set the tab stop or merely to
set the tab stop a certain distance from the current position?
That is, in

123<tab id=foo indent=2>45

should the author expect 2ems worth of space between the 3 and the
4?

- Is there any way to specify absolute tab stops (perhaps as
fraction of prevailing margin)? This would be useful for
specifying totals to be right aligned and also for setting comment
columns in code listings.

- Is it possibile to specify a negative INDENT value? One place
where it would be useful is in setting code listings. Assuming
that INDENT does not imply motion:

<p nowrap>
int f(<tab id="args">int x,<br>
<tab to="args">String s)<br>
{<br>
<tab id="level1" indent=1><tab to="level1">
<tab id="level1lab" indent=-1>s += x;<br>
<tab to="level1lab">members:<br>
<tab to="level1">while (x > 0) {<br>
...
</p>

Evan Kirshenbaum +------------------------------------
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