Comment by gnull
3 years ago
Em-dashes add a bit of a pause. And having them longer and taking a bit more of horizontal space makes it more intuitive. They also break a sentence into parts. Having them easily distinguishable helps navigate text and reduces overhead. Just like periods or paragraph breaks help you see parts of a text, or syntax highlighting helps you see lexemes in a program.
Using just one dash for everything will be readable in a text message or comment. But not in a (complicated) book, because there the benefit of these small things gets multiplied by the scale of the book.
> They also break a sentence into parts.
IMHO, this is the main determination on when I decide to use em-dashes: is the text between them an aside of some kind? An alternatives would be to use parentheses.
Personally I do not find that " - " as the GP suggests enough of a visual cue as "—". And on macOS using different dashes is fairly straight-forward:
* hyphen: the key next to zero, "-"
* en-dash: alt/option-"-": –
* em-dash: shift-alt/option-"-": —
Some apps (e.g. Mail) auto-convert double-"-" into an em-dash as well.
Good to see OSX people thought about this.
On Linux, one needs to enable Compose key (keyboard layout settings). After that, you get default sequences like --. and --- for en- and em-dashes.