Re: Can watermarking Unicode text using invisible differences sneak through Emacs, or can Emacs detect it?

[Richard Stallman]

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  > > Since my terminal handles many of those characters, they work ok for
  > > me.  But there are some it does not support.  Many Vietnamese
  > > characters, for instance.
  > > 
  > > If this feature is implemented to handle ligatures, it could handle
  > > the letters with diacritics too.  That would be as easy as populating
  > > the table of the sequences they stand for.

  > IIUC what you mean by "this feature", we already have that in
  > latin1-disp.el.

It is the same general idea, but (according to the comments at the
start) it handles only the characters in the ISO 8859 character sets.
It should handle all the Unicode characters that could sensibly be
represented as characters to be composed, including ligatures and all
Latin and Greek characters with diacritics.  Maybe some others can be
handled too.

I customized the variable to enable that mode but I don't know how to make it 
actually do
anything.  Maybe it needs something else to truly enable it.

I inserted ẵ (latin small letter a with breve and tilde); it does not
do anything special to that.

  > Given the enormously large number of such sequences, I doubt that
  > terminfo is the right means for determining which sequences are
  > supported.  We have a solution for the Linux console,

We do?  What is it?

  >  and for the rest
  > we allow the user to customize the value of auto-composition-mode to
  > disable it if the terminal misbehaves with these sequences.

We are talking about different issues.  I am talking about how to display
complex characters _in the buffer_.  NOT generated by auto-composition.

I don't think auto-composition does anything in my Emacs.  If I insert
an f and an i in the buffer, they display as two characters, f followed by i.
Not as a ligature.

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)