[Tex2002ans]

Originally Posted by graycyn

That's probably because I was struggling with getting it typed *here*.

Okay. Just wanted to make sure.

Originally Posted by graycyn

In Sigil, I have the word joiner as a preserved entity, so I *do* see it.

What's the word joiner entity?

Originally Posted by graycyn

But I think it was disappearing *here* while I was typing and I didn't realize, so I was typing it in again, and apparently again. Sorry!

Also, I assume buggy implementations in programs too.

I copied/pasted your post into Notepad++ and saw very odd display issues on the WORD JOINER line. (Parts of the text appeared bold.)

Then it had VERY odd:

• highlighting of words
• placement of | when clicking in the line

I haven't ever tested the WORD JOINER inside of ebooks, across devices/apps, but similar bugs may carry over there too.

(For example, when trying to search or drag your finger to highlight text for notes.)

Originally Posted by graycyn

Good, I didn't think so. I never see commas breaking off.

In one of those linked posts, I linked to the actual Unicode linebreaking specs.

The EM DASH is in a unique class all on its own:

B2: Break Opportunity Before and After (B/A/XP)

• 2014 EM DASH

The EM DASH is used to set off parenthetical text. Normally, it is used without spaces. However, this is language dependent. For example, in Swedish, spaces are used around the EM DASH. Line breaks can occur before and after an EM DASH. Because EM DASHes are sometimes used in pairs instead of a single quotation dash, the default behavior is not to break the line between even though not all fonts use connecting glyphs for the EM DASH.

Some languages, including Spanish, use EM DASH to set off a parenthetical, and the surrounding dashes should not be broken from the contained text. In this usage there is space on the side where it can be broken. This does not conflict with symmetrical usages, either with spaces on both sides of the em-dash or with no spaces.

I can't recall seeing anything that actually does language-aware linebreaking, but I have seen differences in linebreaking across apps. (Like when I tested THIN SPACE back in 2016.)

Originally Posted by graycyn

I like modern AND old styles. Not to the extent of trying to duplicate all the crazy spacing from 1910, but the little oddities like the commas and em-dashes add charm and give me that old book feeling.

That wasn't "crazy spacing". Just different rules/kerning.

For readability, certain punctuation got (differently-sized) space around it.

Back then, there was more judicious usage of all the different types of spaces:

• U+2000 = EN QUAD
• U+2001 = EM QUAD
• U+2009 = THIN SPACE
• U+200A = HAIR SPACE
• [...]

Throughout the 20th century—because of technological/economic reasons—most editing/typography boiled down further and further towards "no space" or "single space".

Currently, the only real places these spaces still exist is:

• Maths / Science
  
  • Especially Units + Equations
    
  • For all details/examples of usage, see: "Mathematics into Type" by Ellen Swanson (PDF) (American Mathematical Society, 1999).
• Languages where punctuation-spacing still matters
  
  • Like French « guillemets ».
• Hidden inside font kerning tables.

* * *

Side Note: If you want some interesting history on this, it's similar to the myth that "double space after period is wrong":

• Heraclitean River: "Why two spaces after a period isn’t wrong (or, the lies typographers tell about history)"

In that blog post, he goes through and explains the older typography / Style Guides.

For example, EM QUADs were put after sentence-ending periods.

Side Note #2: It's only been recent that proper typographical spacing has been making a resurgence.

LaTeX has been holding strong, enabling the older (better) style of typography. (See my Units post above.)

And while searching for some info, I just ran across this article with some good examples:

• Smashing Magazine.com: "Micro-Typography: How To Space And Kern Punctuation Marks And Other Symbols"

Finally, the web is also gaining some of this stuff, slowly. And fonts are always getting better kerning inside (so a lot of this spacing issues can be handled more automatically).

Originally Posted by graycyn

Meanwhile, anyone who objects to me just letting the text flow, speak up. The book is for MobileRead, so I'm happy to do what folks prefer, if, of course there is any consensus at all on that.

Meh, if you want to do all those WORD JOINERS and do them properly, have at it. :P

Maybe yours can be the EPUB everyone points to on how to do them properly. (And use it to test across real-life devices.)