Re: [Groff] Typesetting dashes

[Steve Izma]

On Tue, Nov 19, 2013 at 03:58:00PM +0100, Tadziu Hoffmann wrote:
> Subject: Re: [Groff] Typesetting dashes
> 
> > Adding the same amount of stretch to each of the objects in
> > the line maintains symmetry and rhythm.
> 
> I contest that.  Adding the same amount of horizontal motion
> to all spaces, regardless of their natural width, changes
> the relative proportions.  In the limit of large stretch, the
> width of a thinspace will approach that of a regular space.
> But this begs the question of why you wanted a thinspace in
> the first place, instead of a regular space.

Let me rephrase my point (quoted below) about "pulling them
together"; maybe "holding" is a better word. It seems to me that
the purpose of fixed spaces -- em, en, and thin -- is to hold
things together (there's a fourth, traditionally -- maybe called
a "narrow space" or a "hair space"?).

An en space is supposed to be the same width of a numeral (or, at
least of "lining" numerals, typically used in tabular material).
It is frequently used in lists, endnotes, or footnotes to fix the
space between the digit (with, possibly, its punctuation) and the
word immediately following it. That space can't stretch along
with word spaces, obviously, or the left margin of the text would
be ragged.

Similarly, an em space is used to hold the first word in a
paragraph to a particular position, consistently paragraph after
paragraph. I can't think of any other normal use of an em space;
traditionally, it might have been used for lining up tabular
material, but then it became more common for digit spaces (en
spaces) to vary from the traditional one-half em space due to
wilder font designs, so you can't always count on an em space
being equal to the width of two digits. Maybe the em space,
reduced to almost just one function, is becoming obsolete. On the
other hand, groff doesn't have an em space.

I'm not sure about rules for locales that use a space instead of
a comma to separate digits, but I assume it ought to be a thin
space so that the different parts of the number hold together in
the event of stretches to the word spaces in the rest of line.
Presumably you'd always want the space between the digits to be
smaller than the word spaces, and if it were to stretch even
proportionately on one line and not as much on the next, I think
it would look very odd.

> > My problem with a dash joined to adjacent words with a small
> > fixed space or no space is that it can easily pull those
> > words together; yet in terms of readability those words
> > have a weaker relationship to each other than they do to the
> > rest of the words in the phrase they are part of, so pulling
> > them together makes them look almost like a compound word,
> > especially if the spaces on the line are stretched.
> 
> Here I agree with you 100 percent.  That's why I'd want a
> stretchable space instead of a fixed space.  My choice would
> be a three-quarters emdash surrounded by thinspaces (half a
> normal space) (which, incidentally, will have the same width
> as an em-sized dash if the regular space is nominally 1/4 em).
> However, a stretchable thinspace whose width remains half that
> of a normal space when the line is spread cannot currently
> be had with groff.

So does this mean that you are arguing for a new set of spaces
that behave like word spaces but have a different starting
width and stretch proportionately (more or less) along with
word spaces? (That means they would also need to shrink
proportionately as well.)

I'm thinking about the use of spaces traditionally and you're
thinking, I believe, about more creative design. Your idea of
a stretching "fixed" space has appeal in some situations, but
obviously the stretch would be undesirable elsewhere. Your
suggestion requires much more attention to detail (definitely
a mark of craft). Sometimes we can afford that and sometimes
not. And, of course, adding these to groff would require an
overhaul of the H&J routines, not just the addition of new escape
characters, because these things would behave unlike any other
objects in the system.

Yet I'll admit that my idea of dashes is not traditional: I
consider a dash not to be a punctuation mark affixed to another
object (e.g., as a period to a sentence or a comma to a phrase),
but more like an operator between two parallel clauses -- like
the boolean "and" and "or" between expressions. So it's related
to but independent of its surroundings, and using the currently
available stretchable word spaces clarify that relationship.

Hmmm, trying figure this out has "stretched" my brain to limit
for tonight.

        -- Steve

-- 
Steve Izma
-
Home: 35 Locust St., Kitchener N2H 1W6    p:519-745-1313
Work: Wilfrid Laurier University Press    p:519-884-0710 ext. 6125
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