space, minus, space is on the same level as manually typing two spaces after a period

How so? One is the only way to approximate an en or em dash on a typewriter or in a charset that doesn’t have one, the other seems like a workaround of a typesetting bug at best.

-, --, --- is, IIRC, how it is done in LaTex and would be exceedingly simple to do on a typewriter. That being said, to break up sentences I use " -- " because I think it looks nicer than "---". I'll go now ;)

LaTeX is a markup language though, not ASCII art. I can get behind two dashes as a substitute if no en dash is available, but three seems too much and looks like halfway to a horizontal line to me ;)

Until ~10 years ago, I used to type two spaces after a period.

I still do, and I maintain that it’s easier to read text with double spaces after periods.

TeX puts more space after periods/fullstops (which is why you're supposed to do special markup or other measures to mark '.' in the middle of sentences which aren't sentence-enders (e.g. like e.g.)). But it's generally smaller than the equivalent of two manual spaces.

(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 used to feel similarly. Now I find the double space a visual distraction that doesn't in any way improve readability.

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.

I'm still doing it when I am typing at a physical keyboard. Hard habit to break. I learned it so long ago too.

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

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

Haha I learned to type organically, and it was only in my mid-40s that I retrained myself to type the correct way. It took something like 40 hours of practice on keybr.com before I could get close enough to my regular typing speed, such that I could switch over to the 'correct' method without it impacting my work.

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

Most word processors can be configured to flag double spaces. That gives feedback to break the habit.

en-US style is a single em-dash. en-GB style is a single en-dash with spaces on either side.

I was under the impression that you do "-" for hyphen, "--" for En dash, and "---" for Em dash. IIRC, LaTeX (or maybe the editor, it has been some time) even helpfully changes that for you to the correct dash.

Google Docs also does these replacements.

> I was under the impression that you do "-" for hyphen, "--" for En dash, and "---" for Em dash. IIRC, LaTeX (or maybe the editor, it has been some time) even helpfully changes that for you to the correct dash.

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).)

British typesetting style is a little different from US style in the way dashes are presented. In the UK, you might see a thin-space--en-dash---thin-space where a US typesetter would use a em-dash. Typewriter style generally follows books style. Since typesetters no longer use an extra space after punctuation, it's vestigial in typing.