John Cowan <xxxxxx@ccil.org> writes:

> You talk as if you know what characters are, but I don't (in a precise
> technical sense).  Can you please explain what you mean by "characters"?

I mean what the Unicode specification refers to as an "abstract
character".  Encoding a character with Unicode may take one or more
code points.  It is a very close concept to a grapheme, with the
caveat that "grapheme" is relative to a specific writing system, and
"abstract character" is supposed to be an interlingual thing.

> Even if you do have a precise technical meaning for "character", and
> you decide your editor needs to be able to itersate through its buffer
> by character, how is that different from being able to iterate by words
> or sentences or paragraphs?

Who said it was different?  What is perfectly clear however, is that
the one operation that is utterly useless is iterating by code point.

> That is indeed a fine thing if you know what characters are.
> In particular, is the number of characters finite or countably infinite?

No need to specify.  There is no advantage for standardization to
insist on either answer to that question, any more than it does for
numbers.

Thomas