Re: zero-width space (was Re: How to print a literal '.' as the first character in a line?)

[Deri]

On Sunday, 5 June 2022 02:58:14 BST G. Branden Robinson wrote:
> A big problem with "zero-width space" is that it falsifies the statement
> that adding a newline or multiple (regular) space characters after a
> candidate end-of-sentence character results in inter-sentence spacing
> being added.  (Unless there's a break for some other reason, of course.)
> 
> A novice could quite easily reason that something we go to the trouble
> of _calling a space_ behaves like one--but it doesn't.  Zero-width?
> Sure.  But _this_ space _cancels_ end-of-sentence detection.

I thought that the end of sentence detection relied on seeing regular spaces 
after the period, as 
you stated above. Only actual typed spaces will trigger the behaviour. If you 
follow the period 
with any of the other types of space, end of sentence is not triggered. So \& 
is behaving just the 
same as its other unbreakable space cousins. It is not special, it cancels end 
of sentence detection 
simply because it is not a regular space. Our friend the \Z'' also cancels the 
behaviour as well.

If your novice reasons that anything we call a space can be used instead of 
multiple regular 
spaces to trigger end of sentence detection, they will be disappointed because 
they all prevent 
detection just the same as \&.

You may want to mention its use in preventing groff recognising ligatures. 
Typing reff\&ind will 
prevent the fi ligature being used.

Cheers

Deri