https://practicaltypography.com/one-space-between-sentences....
You wouldn't publish anything with line breaks between sentences either. Double spacing or line breaks both work nicely for semantic purposes because html (or markdown which almost always ends up displayed somewhere as html) will ignore it.
Any print publishing software in the 21st century should be aware that two spaces in a prose text source is a hint for a sentence break, and treat it appropriately. They often apply custom spacing (slightly more than 1, but nowhere close to 2) between sentences anyway. Without the two spaces, they have to algorithmically guess at sentences. You just won't notice when there are sentence detection errors, unless you're a typography fanatic; who's going to notice 1 space instead of 1.2 or whatever the optimum happens to be?
What extra information is encoded by fullstop + 2 spaces?
> Good typography seems to dictate a wider space after a sentence than between words.
You:
> Rendering engines can do anything they want. The question is about source representation only, for semantic purposes.
The thread you’ve commented on is literally about rendering, not source representation and semantics. I agree that you can use a double-space as a sentence delimiter, but we’re currently discussing whether it’s “good typography” to render it that way.
I don't think there's much dispute that two spaces is too much in modern properly rendered prose, so I don't know who "we" is. (And anyone who does think two word spaces is just fine, would probably also agree that it should be configurable and not dependent on two spaces in the source text.)
If there's a text renderer out there that renders two spaces as two word spaces in prose, that should be patched, not writers' brains.
Studies examining whether or not wider spacing between sentences improved readability have been inconclusive.
There is one good reason to use two spaces between sentences, at least for text that's going to be processed automatically. It can be very difficult for software to know whether a given punctuation mark is the end of a sentence or something else, like an abbreviation. GNU Emacs, for example, is (or was) coded to recognize sentences by looking for two spaces after a ., ?, or !.[1]
1 https://www.gnu.org/software/emacs/manual/html_node/emacs/Se...