Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!cs.utexas.edu!uunet!yale!leichter
From: leichter@CS.YALE.EDU (Jerry Leichter)
Newsgroups: comp.text
Subject: Re: em-dashes
Message-ID: <65590@yale-celray.yale.UUCP>
Date: 6 Jul 89 16:49:13 GMT
Sender: root@yale.UUCP
Organization: Yale Computer Science Department, New Haven, Connecticut, USA
Lines: 69
X-from: leichter@CS.YALE.EDU (Jerry Leichter (LEICHTER-JERRY@CS.YALE.EDU))

In article <1168@atanasoff.cs.iastate.edu>, jwright@atanasoff.cs.iastate.edu (Jim Wright) writes...
>In article <65479@yale-celray.yale.UUCP> leichter@CS.YALE.EDU (Jerry Leichter (LEICHTER-JERRY@CS.YALE.EDU)) writes:
>	[ help with someone else's problem...]
>| BTW, you might want to look at the actual text being used in this memo and
>| compare it what the LaTeX book says about various typographical conventions.
>| For example, read the LaTeX book's discussion of where to use n-dashes (--)
>| and where to use m-dashes (---).
> 
>OK, I've wondered for a long time, now I'm going to ask.  Should em-dashes
>have surrounding spaces or "bump-up" against the surrounding words?
> 
>(1)  This might be correct --- but is it?
>(2)  This might be correct---but is it?
> 
>So which is correct, and why?
> 
>-- 
>Jim Wright
>jwright@atanasoff.cs.iastate.edu

I've wondered about this myself - and I've never been able to find any hard
and fast rule on the matter.  For example, the Chicago Manual of Style has
two pages discussing the use of dashes of various sorts, but never mentions
the issue of spacing for em-dashes.  All the examples they give use no spaces
before or after.  The TeXbook doesn't say anything about it; the LaTeXbook
says that spaces should NOT appear (page 14).  Neither uses spaces.

On the other hand, I have seen texts, which seem to be set to high typographi-
cal standards, which DO use spaces before and after em-dashes.  (I can't think
of any off-hand, though.)

One book on typography that I have handy (Brady's "Using Type Right") - says
that in a well-designed font, an em-dash should have a built in "shoulder"
to keep it from touching the adjoining letters.  This is not the case in some
fonts; Brady advises that the compositor should add a thin space before and
after in this case.  BTW, the CMR em-dash is designed "correctly" according
to this criterion.  On the other hand, the font used in the Chicago Manual
of Style seems pretty marginal to me.  (In the 13th Edition, take a look at
the first example in Section 5.83.)

So...the concensus seems to be "no spaces".

The rules on this sort of stuff can be pretty arbitrary.  For example, there
seems to be universal agreement that an ellipsis should be treated as a word,
with normal word spacing before and after.  Why the difference?  I'd have
expected that, if anything, you could get away with LESS space around an
ellipsis than around an em-dash, since you have some much white above and
around those little dots to begin with.

One thing to keep in mind is that, for economic reasons, typographical con-
ventions will usually be biased toward the smallest spacing possible, at
least for running text.  (Headings and such are a different issue, but they
have a lesser, (trivial for something like a book), influence on over-all
text length.)

Any good text on typography will tell you that you should first learn the
rules so that when - not if! - you later break them, you understand what you
are doing.  It's probably hard to come up with ANY typographical rule which
cannot be constructively broken - though for some you'd really have to search
hard for an example!

Finally, I'll confess that I personally put spaces around CMR em-dashes.  I
started off doing it without thinking - I just copied my normal ASCII conven-
tions without realizing what I was doing.  Later, I started wondering, and
checked some references.  (Curiously, I never noticed the line in the LaTeX-
book before.)  When all was said and done, however, em-dashes with spaces
around them just look cleaner and more open to me; em-dashes without spaces
look crowded.
							-- Jerry