How to Use Em Dashes (–), En Dashes (–), and Hyphens (-)

Some style guides recommend "space, en dash, space" for this, and I prefer that myself – mainly because some software doesn't treat em dashes correctly as word separators for double click selection purposes.

For example, I'm pretty sure that at least some Kindle models would highlight both the word before and after the em dash when selecting one of them, which makes using the dictionary very annoying.

The first keyboard I used was my dad's typewriter, and I don't recall it having any 'dash' other that the minus sign.

Which one does that? I threw up a little in my mouth and wish to avoid such style guides in the future!

  <word> <space> <dash> <space> <word>

  <word> <dash> <word>

That one I’d usually parse as a hyphen, as in e.g. well-known. “Word space dash space word” is much clearer, in my view.

> The AP Style Manual, a/the leading source for US journalism

One of the things I can easily get away with by not being a US journalist :)

It’s very common outside of America, even in English.

The last paragraph of the article also addressed the subjective nature of spacing around the em dash:

> Spacing around an em dash varies. Most newspapers insert a space before and after the dash, and many popular magazines do the same, but most books and journals omit spacing, closing whatever comes before and after the em dash right up next to it.

As far as the selection detail, did you mean that you replace an em dash used like a comma or parenthesis with spaces and an en dash for specific highlight performance issues? Surely the spaces and an em dash would alleviate the selection highlight behavior and not muddy the waters of when to use an em vs. an en dash?

self-fulfilling

self—fulfilling

One of these looks very, very wrong.

Basically, we didn’t like some things in AP but we wanted to make it easy for journalists to copy/paste.

(A nice thing in (La)TeX is that one could follow the "two spaces after a full-stop" rule, which then has the advantage of being an explicit marking for sentence boundaries (which your editor might be able to navigate; Emacs has a convention of assuming two spaces after a sentence-ending '.'), but then the TeX typesetting will take care of making it look right. I lost the habit of actually doing this, for better or worse, except when flycheck/checkdoc/package-linter.el makes me do it for docstrings.)

(I also now looked up and found out that in Spanish, apparently, you are supposed to put space only on one side of the dash, when used as a direct speech separator.)

The effect of the double space is, I suspect, a product of the reader's expectations: if you expect it, its absence creates mental work, detracting from readability; if you don't expect it, its presence is what creates mental work.

That’s one thing I really like about English: There’s no central authority decreeing what’s right and what’s wrong top down, and it feels like there is some room for individual preferences and experimentation.

Very refreshing, compared to e.g. German, which has more than one semi-official authority gate keeping “correctness” in speech and writing.

Why yes, I did list the opposite behavior as an advantage of each. Because that, too, is up to individual preference. :-)

It's funny that they omit to mention the possibility of setting it off with a thin space ' ' or hair space ' ' (those are the thin-space and hair-space Unicode characters, though they show up full width for me), which I thought was preferred typographic practice.

(On Googling, maybe the reason that they don't mention it is that I was imagining it; I can't find any evidence for my belief.)

The conversion of '--' to an en dash and '---' to an em dash is done by the TeX compiler, and appears in the rendered file, but I think that most TeX editors don't change the TeX code itself. (This is distinct from XeTeX-based compilers, which can handle non-ASCII Unicode characters like the em dash '—' directly in the source.)

(I think that the article's point is that, in some fonts, -- (two hyphens) is literally the (approximate) size of an em dash, not that it is always understood as meaning an em dash. At least in my font, --- (three hyphens) is far too long to literally look like an em dash:

---

--

—

–

(in order, three hyphens, two hyphens, em dash, en dash).)

If you want to not have a line break, you shouldn't rely on arbitrary behavior. You should use non-breaking characters like non-breaking spaces and word joiners.

For what it's worth, I was in the last class in my high school to learn typing on IBM Selectric typewriters. We were taught to type two spaces, two hyphens, then two spaces. Incidentally, we were taught two spaces after periods and colons. To this day, I find it hard to read text that doesn't have proper spacing after periods. (HTML and WYSIWYG word processors handle formatting, but e.g. fixed-font text editors don't)

Interestingly, at least in my browser and grabbing the direct link to the comment with curl, show the bytes as 0x20 for both. Perhaps the comment submission handler, or even the browser, collated your more specific U+2009 (thin) and U+200A (hair) spaces into the regular U+0020 space?

I've definitely noticed the behavior you describe on some layout engines, too, and it's another reason why I personally prefer "foo – bar" style.

You can tell when I've edited something on both a phone and a physical keyboard, based on the inconsistent use of spaces.

Probably! I think HN strips out emoji; maybe it just takes the safest approach and strips out all non-white-listed Unicode.

  Hard habit to break. I learned it so long ago too.

Retraining myself to stop doing double-spaces took maybe a week.

That's an interesting practicality but I don't think it's the cause of the rule: The rule probably long predates automated line breaking. Also, I think automatic line breaking will break compound words at the hyphen; it doesn't require spaces (which is also obvious from a software development point of view: the logic is relatively simple either way):

  Lorem ipsum dolor sit amet, consectetur adipiscing double-
  decker lorem ipsum dolor sit amet, consectetur ...

The old typewriter typefaces were monospaced, ie. every character was the same width, but this is no longer the case. Virtually all typefaces today are proportionally spaced, not monospaced. So it’s redundant to leave extra room after periods.

I've come to the conclusion it boils down to which style manual one follows. I've taken a careful look at numbers of high-end books which no doubt have been carefully typeset and I've found EM dashes with and without spaces.

It seems there is no definitive rule but I might be wrong.

My comment applies to a few pedantics I know personally, who stubbornly double space after periods when typing in regular situations.